10th grade physics problem solving

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PHYSICS

ISSUES 10

10th grade problems and a set of test questions

Exercise 1

Issue 1.

It took the motorboat 1,8 hours to reach the destination on the river and 2,4 hours to return. If so, how long will it take to reach the destination? (Answer: 14,4 hours).

Given     the time of arrival of the sol

Solution:

Issue 2

An escalator on the subway takes a person up in 30 s. If the person and the escalator move together, it rises at 10 s. How long does it take for a person to get up when the escalator is quiet? (Answer: 15 s).

Given

Solution:

Issue 3

The body is falling freely from a height of 80 m. Find the displacement in the last second of the descent. Determine the average speed during the movement. Assume that the initial velocity of the body is zero. (Answer: 35 m, 20 m / s).

Given

Formula:

Solution:

Issue 4 If an object thrown vertically upwards has traversed the last 1/4 of a path in 3 s, how long has it risen? What was his starting speed? (Answer: 60 m / s, 6 s).

Given

Formula:

Solution:

Issue 5

If an object descending freely without initial velocity travels 75 m in the last second, at what height did it descend? What is the speed at the end of the movement? (Answer: 320 m, 80 m / s).

Given

Formula:

Solution:

Issue 6

Two bubbles were thrown vertically upwards from a point with an initial velocity of 20 m / s at 1-second intervals. How long after the first balloon is fired do the balloons meet? (Answer: 2,5 s).

Given

Formula: 1 - we calculate the body 2 -

Solution:

    2,5 s, 1,5 s

Issue 7

What is the radius of the flywheel if the speed of the points on the flange when the flywheel rotates is 6 m / s and the speed of the points at a distance of 1,5 cm from the axis is 5,5 m / s? (Answer: 18 cm).

Given

Formula:

Solution:

8-masala. Mechanical motion is transmitted from wheel I to wheel II via a belt. If the angular velocity of wheel II is 100 ps – 1 and the radii of the wheels are 30 and 10 cm, respectively, how many times per minute does wheel I rotate? (Answer: 300 times).

Given

Formula:

Solution:

Issue 9

The tape recorder wrapped the tape at 4 m at a speed of 40 m / s. If the starting radius of the wrapper is 2 cm and the final radius is 6 cm, determine the thickness of the tape. (Answer: 0,063 mm).

Given

Formula:

Solution:

    d = Rr

Issue 10

 What horizontal velocity must be thrown from a height h / 3 so that an object thrown horizontally from an altitude h falls exactly to the point where it falls?

Given

Formula:

Test questions for completing Chapter I.

1. The speed of a motor boat is 6 m / s relative to the shore when swimming along the river, and 4 m / s when swimming against the current. What is the velocity of the river (m / s)?

2. A) 0,5; B) 1; C) 2,5; D) 5.

3. The object was thrown vertically downwards at a speed of 15 m / s. What speed (m / s) does it reach after 2 hours?

4. A) 25; B) 35; C) 30; D) 45.

5. At what speed does the object shoot vertically, does it fall back to the place of shooting after 6 s (m / s)?

6. A) 20; B) 35; C) 30; D) 40.

7. The velocity of an object thrown vertically upwards decreased twice after 2 h. How fast was he shot?

8. A) 30; B) 40; C) 50; D) 60.

9. Two metal bubbles with masses of 100 g and 150 g were thrown vertically upwards at the same speed. Which one of them rises higher? Ignore air resistance.

10. A) a balloon of small mass;

11. B) n ball with large mass;

12. C) both rise to the same height;

13. D) the information provided is insufficient.6. The rotational motion is transmitted from a wheel with 50 teeth to a wheel with 150 teeth. What is the rotation period of the second wheel if the first wheel rotates completely once in 2 s?

14. A) 3 s; B) 7,5 s; C) 5 s; D) 6 s.

15. Which of the following quantities does not change in a curvilinear straight motion?

16. A) instantaneous speed module; B) acceleration module;

17. C) average speed modulus; D) acceleration vector.

18. What is the direction of the acceleration vector in a curvilinear straight motion?

19. A) to the center along the radius of curvature of the trajectory;

20. B) attempt at trajectory;

21. C) on the trajectory of movement;

22. D) out of center along the radius of the curve.

23. From a tower 125 m high, the object was fired in a horizontal direction at a speed of 30 m / s. Determine the flight distance of the object.

24. A) 300 m; B) 120 m; C) 240 m; D) 150 m.

25. The object was fired from the ground at an initial speed of 30 m / s at an angle of 20 ° to the horizon. Determine the horizontal and vertical components of the initial velocity vector (m / s).

26. A) 10 and 14,1; B) 17,3 and 10; C) 14,1 and 10; D) 20 and 10.

S	1	2	3	4	5	6	7	8	9	10
J	B	B	C	B	C	D	A	A	D	B

Exercise 2

Issue 1

The roof of the house is 30o above the horizon. When a person walking on the roof has a coefficient of friction between the sole of his shoe and the roof, can he walk without slipping? (Answer: 0,58).

Given

Solution:

Issue 2

Loads of 50 g and 75 g are hung on the ends of the rope passed through the fixed block. The mass of the rope and block is insignificantly small. Assuming that the rope is not elongated, find the acceleration of the movement of the loads and the tensile strength of the rope. (Answer: 1,96 m / s2; 0,6 N).

Given

Solution:

Issue 3

There is a container of liquid on the cart. The car is moving in an horizontal direction with an acceleration a. What angle does the liquid make with the horizon when the surface is in a stable state? (Answer: a = tga).

Given

Solution:

Issue 4

An object that began to move under the influence of a constant force traveled 0,5 m in the first second. If the mass of the body is 25 kg, what is the force acting? (Answer: 25 N).

Given M = 25 kg S = 0,5 m

Solution:

Issue 5

An object of mass 50 g, which began to move under the influence of a constant force, traveled 2 m in 1 seconds. What is the force acting? (Answer: 0,025 N).

Given m = 0,05 kg t = 2 s S = 1 m F =?

Solution:

Issue 6

The body is floating in a bucket of water in the elevator. If the lift moves up (down) with an acceleration, will the sinking depth of the body change?

Given  if  increases  decreases.

Issue 7

A thread is wound on a cylinder of mass M. The cylinder is then dropped and the thread is pulled up. In this case, the center of mass of the cylinder remained at the same height during the spread of the thread. What is the tensile strength of the rope?

Given m = M T =? Solution:

Issue 8

There is a load on the horizontal board. The coefficient of friction between the load and the plate is 0,1. What acceleration is given to the board in the horizontal direction when the load on it slips? (Answer: 1 kg).

Given   Solution:

Issue 9

There is a straight cylinder on a sheet of paper. The height of the cylinder is 20 cm and the diameter of the base is 2 cm. With minimal acceleration, the cylinder will overturn. (Answer: a = 0,1 m / s2).

Given

Solution:

h       ma

Issue 10

The unloaded vehicle, which weighed 6 t, began to move with an acceleration of 0,6 m / s2. What is the mass of the load placed on it if it is driven by a gravitational force with an acceleration of 0,4 m / s2? (Answer: 3 t).

Given

Solution:

 

 

Test questions on the completion of Chapter II

1. Fill in the blanks. Number systems that are stationary or moving in a straight line are called….

2. A)… relative number systems; B)… inertial reference frames;

3. C)… noninertial systems; D)… Absolute number systems.

4. How does an object of mass 10 kg move under the action of a force of 20 N?

5. A) flat at a speed of 2 m / s;

6. B) accelerating with an acceleration of 2 m / s2;

7. C) decelerating with an acceleration of 2 m / s2;

8. D) Flat at a speed of 20 m / s.

9. A man with a mass of 1 kg is standing in an elevator going up with an acceleration of 2 m / s50. What is the weight of a person (N)?

10. A) 50; B) 500; C) 450; D) 550.4. Loads of masses m1 and m2 are suspended on a fixed block by a rope. How fast do they move? Let m1 <m2 be taken.

11. A) a = g; B) a = g; C) a = g; D) a = 0.

12. In what motion of the elevator does the load on the body in it occur?

13. A) Upwards with constant speed;

14. B) Down with constant speed;

15. C) With upward constant acceleration;

16. D) When the elevator is stationary.

17. What is meant by the geostationary orbit of a satellite?

18. A) The minimum orbit of the satellite from the Earth's surface;

19. B) The maximum orbit of the satellite above the Earth's surface;

20. C) The orbit of the satellite at a certain height above the Earth's surface;

21. D) An orbit in which the astronauts make observations on the satellite.

22. If two opposing forces of 60 N are placed on the ends of the dynamometer, how many newtons will the dynamometer show?

23. A) 15; B) 30; C) 60; D) 120.

24. The forces 3 N and 4N are placed at one point. The angle between the directions of force is 90 °. What is the modulus of equal force (N)?

25. A) 1; B) 5; C) 7; D) 1.

S	1	2	3	4	5	6	7	8
J	B	B, C	D	A	C	C	C	B

Exercise 3    Problem 1 A 0,3-ton wagon moving at a speed of 20 m / s overtakes a 0,2-ton wagon moving at a speed of 30 m / s. If the collision is inelastic, what will be the speed of the wagons after they collide?

Given

Solution:

Issue 2

How much work does a person do when he lifts a body of mass 2 kg to a height of 1 m with an acceleration of 3 m / s2? (Answer: A = 26 J).

Given

Solution:

Issue 3

What is the kinetic energy of a 6,6-ton spacecraft moving in orbit at a speed of 7,8 m / s? (Answer: Ek = 200 GJ).

Given

Solution:

Issue 4

What are the potential and kinetic energies of a body of mass 5 kg falling freely from a height of 3 m at a height of 2 m above the ground? (Answer: Ep = 60 J; Ek = 90 J).

Given

Solution: - or

5m 2m

Issue 5

What is the initial velocity 2 that must be thrown below the height h in order for the ball to return from the ground and rise to a height of 0h? Let the collision be considered absolutely elastic.

Given

Solution:

2h h

Issue 6

A point of mass 1 kg is moving flat in a circle at a speed of 10 m / s. Find the change in momentum in a quarter of the period, half of the period, the entire period. (Answer: 14 kg · m / s; 20 kg · m / s; 0).

Given

Solution: Pythagoras

Issue 7

An object with a mass of 0,5 kg was thrown vertically upwards at a speed of 4 m / s. Find the work done by gravity, the change in potential energy and the kinetic energy as the body rises to its maximum height. (Answer: 4 J; 4 J; - 4 J).

Given

Solution:

Issue 8

Inelastic spheres with masses of 1 kg and 2 kg are moving towards each other at speeds of 1 and 2 m / s, respectively. Find the change in the kinetic energy of the system after the collision (Answer: 3 J).

Given

Solution: = 1,5j

Issue 9

A trolleybus with a mass of 15 t was driven from its place with an acceleration of 1,4 m / s2. The coefficient of resistance is 0,02. Find the work done by gravity and the work done by resistance in the first 10 m of the road. How much kinetic energy did the trolleybus get? (Answer: 240 kJ, - 30 kJ, 210 kJ).

Given

Solution: Ek=

Issue 10

The sledge descends from a hill with a height of 2 m and a base of 5 m and stops after crossing a horizontal path 35 m from the base of the hill. Assuming that the friction is the same throughout the path, find the coefficient of friction. In an experiment with a similar method, find, for example, the coefficient of friction between the matchbox and the ruler. (Answer: 0,05).

Given

Solution: Method 1

h                           l      S                       a

A = E_p     

= 0.05

Method 2

 

Test questions on the completion of Chapter III

 

1. … Is a quantitative measure of various forms of actions and interactions. Fill in the blanks.

2. A) Energy; B) Potential energy;

3. C) Kinetic energy; D) Electric energy.

4. What is the unit of energy in SI?

5. A) Watt; B) Joul; C) Calories; D) N · m.

6. … Is the magnitude of the force equal to the scalar product of the displacement that occurs under the influence of that force. Fill in the blanks.

7. A) Energy; B) Potential energy;

8. C) Kinetic energy; D) Mechanical work.

9. Energy never disappears or emerges from nothing, it can only be transformed from one species to another. What is this?

10. A) Newton's first law; B) Newton's second law;

11. C) The law of conservation of energy; D) Newton's third law.5. What is the ratio of useful work to full work?

12. A) Energy; B) Potential energy;

13. C) Kinetic energy; D) FIKni.

14. The… of a system is the sum of its kinetic and potential energies.

15. A)… energy; B)… total mechanical energy;

16. C)… kinetic energy; D)… mechanical work.

17. … A collision is a very short-term interaction of two or more bodies. Fill in the blanks.

18. A) Absolute elastic; B) Absolute inelastic;

19. C) Collision; D) Migration.

20. … Collision is the collision of two deformable spheres. Fill in the blanks.

21. A) Absolute elastic; B) Absolute inelastic;

22. C) Collision; D) Migration.

23. … Collision is the collision of two non-deformable spheres. Fill in the blanks.

24. A) Absolute elastic; B) Absolute inelastic;

25. C) Collision; D) Migration.

26. The forces that depend on the initial and final state of the body are called… forces. Replace the dots with the correct answer.

27. A)… weight; B)… positive;

28. C)… potential or conservative; D)… man fi y.

S	1	2	3	4	5	6	7	8	9	10
J	A	B	D	C	D	B	A	B	A	C

Exercise 4

Issue 1

Is it possible to pull the rope without hanging?

Given  if not.

Issue 2

A pipe weighing 1,2 · 103 kg is lying on the ground. What force is needed to lift one end of it? (Answer: ≈ 6 · 103 N).

Given

Solution:

Issue 3

The axles on which the car wheels with a mass of 1,35 t are mounted are located at a distance of 3 m from each other. The center of mass of the car is located 1,2 m from the front axle. Determine the forces exerted on each axle of the vehicle.

Given

Solution:  l2= ll1 F1 l1= F2 l2 F1 +F2 = mg F1 1,2 = F2 1,8 F1 +F2 = mg

Issue 4

What force must be exerted on its upper edge to overturn a cube-shaped body? What is the minimum value of the coefficient of friction of the cube on the floor? The side of the cube is a and the mass is M.

a        mg

Solution:

Issue 5

A tall board with a square base stands in a horizontal plane. How to determine the coefficient of friction between the board and the plane using only a ruler?

h             mg

Solution:  falls when it slides.

Issue 6

The body is affected by three forces of magnitude greater than 100 N. If the angle between the first and second forces is 60o and the angle between the second and third forces is 90o, find the equal effector of the forces. (Answer: 150 N).

Given

Solution:  will be relative.

F                   600                       F2            F3

Issue 7

A suit weighing 10 N hangs on a 20 m long drying rope. The suit hanger is in the middle of the hanging rope, 10 cm below the horizontal line passing through the points where the rope is fastened. Find the tensile strength of the rope. (Answer: 500 N).

Given

Solution:             5 m 10 m 10s                                                        mg

Issue 8

Can a box hung with a rope on a vertical wall remain as shown in Figure 4.23?

Given            x                                 N                  N                Mg

Solution: No

Issue 9

The rails, which are 10 m long and weigh 900 kg, are raised by two parallel ropes. One of the ropes is at the end of the rail and the other is 1 m away from the other end. Cables

find the forces of tension. (Answer: 4 kN; 5 kN).

Given

Solution:

mg

Issue 10

A homogeneous heavy metal rod was bent and hung loosely at one end. If the bending angle is 90o, what angle does the hanging end of the rod make with the vertical? (Answer: tga = 1/3).

Given

Solution: P1d1= P2 d2                             Answer: tga = 1/3

Issue 11

Where the river flows fast: in the outer part of the water or at a certain depth; in the middle of a river or near the shore? In the pit

Issue 12

The water supply line was punctured and water began to flow out of it. If the crack surface is 4 mm2 and the water outlet height is 80 cm, how much water is wasted per day? (Answer: 1380 l).

Given  t = 24 * 3600s

Solution

Issue 13

The submarine is floating at a depth of 100 m. A small hole was opened in it during training. If the hole is 2 cm in diameter, how fast does water enter it? How much water enters through the hole in an hour? The pressure inside the ship is equal to atmospheric pressure. (Answer: 44,3 m / s; 50 m3).

Given T = 1 hour

Solution    or

14. The water in the water pipe used for the switch is sar 60 l / min. If the water surface coming out of the pipe is 1,5 cm2, what is the water surface at a height of 2 m?

Given V / t =60l / s S1= 1,5 · 10-4m2 h = 2m S2=?

Solution:

Test questions on the completion of Chapter IV

 

3. The shoulder of strength is….

4. A) the length of the lever;

5. B) the distance from the axis of rotation of the lever to the end;

6. C) the shortest distance from the direction of the force vector to the axis of rotation;

7. D) the shortest distance between pairs of forces acting on a lever.

8. In what unit is the moment of force measured?

9. A) Newton meter (N · m); B) Joul (J);

S) Watt per second (W · s); D) Joules / second (J / s) .7. "The modulus of velocity of an incompressible liquid flowing in a tube of different surfaces is inversely proportional to the surface area of ​​the liquid." What is the name of this confirmation?

1. A) The equation of flow continuity; B) Torrichelli's equation;

2. C) Bernoulli's equation; D) The Magnus rule.

3. A faucet is installed under the cistern, which is 5 m high. How fast does the liquid flow out of the tap when it is turned on?

4. A) 9,5 m / s; B) 95 cm / s; C) 9,8 m / s; D) 10 m / s.

S	1	2	3	4	5	6	7	8	9	10
J	A	C	C	D	B	A	C	C	D	D, C

Exercise 5

Issue 1

The mathematical pendulum oscillated 1 times in 40 min 50 s. Find the period of oscillation and cyclic frequency of the pendulum. (Answer: 2 s, p).

Given

Solution

Issue 2

The equation of vibrational motion is given in the form x = 0,06cos100pt. Find the amplitude, frequency, and period of the oscillating motion. (Answer: 6 cm, 50 Hz, 20 ms).

Given

Solution A = 0,06m = 6cm

Issue 3

The point moves in harmonic oscillation. The maximum displacement is A = 10 cm, the maximum value of velocity = 20 cm / s. Find the cyclic frequency of the oscillations and the maximum acceleration of the point. (Answer: 2 rad / s; 0,4 m / s2).

Given

Solution

Issue 4

A harmonic oscillation with point amplitude A = 0,1 m and period T = 2 s is moving. Find the velocity and acceleration at the moment of displacement x = 0,06 m. (Answer: 0,25 m / s; 0,6 m / s2)

Given

Solution

Issue 5

At what part of the period is the velocity of a point equal to half of its maximum value? The initial phase of the harmonic oscillations is zero. (Answer: T).

Given

Solution

Issue 6

The material moves a harmonic oscillation with amplitude A = 5 cm. If a point is affected by an elastic force F = 0,2 N, find the kinetic, potential, and total energy of the point.

Given

Solution

Issue 7

What is the oscillation frequency (Hz) of a spring pendulum with a mass of 100 N / m and a mass of 10 g? (Answer: 16 Hz).

Given

Solution

Issue 8

How does the frequency of its oscillations change if the spring of a spring pendulum is cut in half?

Given

Solution  increases.

Issue 9

The length of the mathematical pendulum is 2,5 m, the mass of the balloon hanging on it is 100 g. What is the oscillation period (s)? (Answer: 3,14 s).

Given

Solution

Issue 10

A bucket of water with a small hole in the bottom is hanging on a rope. How does the period of vibration change with the decrease of water?

Given

Solution      so

Issue 11

In the same time interval, the first pendulum oscillated 50 times and the second pendulum 30 times. If one of them is 32 cm shorter than the other, find the length of the pendulums.

Given

Solution

Issue 12

A student weighing 20 kg is flying a swing. Find the kinetic and potential energy at 1/15 of the oscillation period if the swing deviates from the equilibrium position by a maximum of 1 m and oscillates 12 times per minute.

Given

Solution

Test questions on the completion of Chapter V.

 

1. How does its period change if the amplitude of the oscillations is doubled?

2. A) increases 2 times; B) decreased by 2 times;

3. C) increases 4 times; D) does not change.

4. If the length of a mathematical pendulum decreases by a factor of 16, how does its period of free (private) oscillations change?

5. A) decreased by 16 times; B) increases 16 times;

6. C) increases 4 times; D) Decreased by 4 times.

7. In what phase do the bubbles oscillate with each other?

1 2 3

1. A) 1 and 3 opposite, phase 2 and 3

the same;

1. B) 1 and 2 are opposite, 2 and 3 are the same;

2. C) 1 and 2 are the same, 2 and 3 are opposite;

3. D) 1 and 2 are opposite, 1 and 3 are the same.

4. In what environments do longitudinal waves propagate? 1 - solids-

yes; 2 - in liquids; 3 - in gaseous substances.

1. A) only 1; B) only 2; C) only 3; D) in 1, 2 and 3.

2. Fill in the blanks. “The vibrations are in the same phase in the environment

is called the orasidagi between the two oscillating points.

1. A)… short-wavelength;

2. B)… large shear amplitude;

3. C)… long distance wavelength;

4. D)… large number of oscillations frequency.6. Fill in the blanks. "Transverse waves are…-waves".

5. A)… compression; B)… expansion;

6. C)… compression-expansion; D)… shift.

7. The period of the wave propagating in the medium is 10 s, the wavelength is 5 m

What is the velocity of propagation of the wave?

1. A) 0,5 m / s; B) 2 m / s; C) 50 m / s; D) 5 m / s.

2. If the amplitude of the material point oscillations is 4 cm, its one

What is the path traveled during full vibration (cm)?

16. A) 0; B) 4; C) 8; D) 16.

17. What is a cyclic frequency?

18. A) the number of oscillations per second;

19. B) the time taken for a single vibration;

20. C) the number of oscillations in 2 seconds;

21. D) the change in angular velocity in 1 second.

22. A load of 160 g was suspended on a spring with a height of 400 N / m. Produced

what is the oscillation frequency of the pendulum (Hz)?

20. A) 1,6; B) 3,2; C) 5,4; D) 20.

S	1	2	3	4	5	6	7	8	9	10
J	D	C	C	D	A	C	A	D	D	B

Exercise 6

Issue 1

How much does the internal energy of 20 g of helium change when the temperature increases by 200 ° C? (Answer: DU = 12, 5 k J).

Issue 2

 How much work is done when 320 g of oxygen is isobarically heated to 10 K? (Answer: A = 830 J).

Given A-?

Solution

Issue 3

15 g of water vapor at 1,5 ° C was introduced into a vessel containing 100 kg of water at 200 ° C. What is the total temperature after the steam condenses? (Answer: t = 89 ° C).

Given

Solution We equate 1 and 2

Issue 4

How much work did he do when he heated 290 g of air isobaric to 20 K, and how much heat was given to him? (Answer: 1,7 kJ; 5,8 kJ).

Given

Solution

Issue 5

When 800 moles of gas were heated isobarically to 500 K, it was given a heat of 9,4 MJ. In doing so, determine the work done by the gas and how much its internal energy has increased. (Answer: 3,3 MJ; 6,1 MJ).

Given

Solution

Issue 6

When 27 g of oxygen with a temperature of 160 ° C were heated isobarically, its volume doubled. Find the work done on the expansion of the gas, the amount of heat required to heat the oxygen, the change in internal energy. (Answer: 12,5 kJ; 44,2 kJ; 31,7 kJ).

Given

Solution

7. The temperature of the heater of an ideal heat engine is 117 ° C, that of a refrigerator is 21 ° C. The amount of heat that the machine receives from the heater in 1 s is 60 kJ. Calculate the FIC of the machine, the amount of heat transferred to the refrigerator in 1 s, and the power of the machine. (Answer: 23%; 146 kJ; 14 kW).

8. In an ideal heat engine, 300 J of work is done for each kilojoule of energy taken from the heater. If the temperature of the refrigerator is 280 K, determine the FIC of the machine and the temperature of the heater. (Answer: 30%; 4 0 0 K).

9. Find the FIC of a tractor engine with a power of 110 kW and a fuel consumption of 28 kg of diesel fuel per hour. (Answer: 34%).

10. If a motorcycle travels at a speed of 108 km / h and travels 100 km and consumes 3,7 liters of gasoline, and the engine's FIK is 25%, what is the average power achieved by the motorcycle engine? (Answer: 8,9 kW).

Test questions on the completion of Chapter VI

1. Show the first law of thermodynamics.

2. A) DU = Q + A; B) Q = DU + A; C) Q = DU - A; D) DU = Q - A.

3. Fill in the blanks. The process that takes place without the exchange of heat with the environment is called the… process.

4. A)… isothermal; B) .. isochoric; C)… adiabatic; D)… isobaric.

5. Fill in the blanks. Coefficient of efficiency of the Carnot cycle

6. A)… equal to one; B)… greater than one;

7. C)… is equal to zero; D)… is smaller than one.

8. The amount of heat does not automatically transfer from a low-temperature body to a high-temperature body. What does this definition represent?

9. A) The first law of thermodynamics; B) Thermodynamic equilibrium;

10. C) II law of thermodynamics; D) Thermodynamic process.

5. Fill in the blanks. A machine that converts the internal energy of fuel into mechanical energy is called….

6. A)… heat engine; B)… heat engine;

7. C)… jet engines; D)… steam turbine.

S	1	2	3	4	5
J	B	C	D	C	A

Exercise 7

Issue 1

 At the two ends of a regular triangle with sides of 10 cm are two charges of - 4 nC and + 4 nC. What is the field strength at the third end of the triangle? (Answer: 3,6 kV / m).

Given

Formula:

+q2 E2 60          E1

Solution:

Issue 2

Inside the dielectric medium, there are two charges with a charge of 6 nC and -6 n C at a distance of 8 cm from each other. What is the field strength between them? (Answer: 140kV / m).

Given

Formula:

Solution:

Issue 3

When a point charge is transferred between two points with a potential difference of 100 V, the field does 5 mJ of work? (Answer: 50 nC).

Given

Formula:

Solution:

Issue 4

A 50nC charge at some point in the electrostatic field has a potential energy of 7,5m J. Find the electric field potential at this point. (Answer: 150 V).

Given

Formula:

Solution:

Issue 5

The two point charges of +0,4 mC and −0,6 mC are spaced 12 cm apart. What is the electric field potential between the cross-sections connecting the charges? (Answer: –30 kV).

Given

Formula:

Solution:

Issue 6

Two point charges with a charge of 3 · 10–8 C are located in the air at a distance of 50 cm from each other. What work needs to be done to bring them closer to 20 cm? (Answer: 10,8 mJ).

Given =q

Formula:

Solution:

Issue 7

If the distance between two charged parallel plates is 12 cm and the potential difference is 180 V, determine the field strength between the plates. (Answer: 1500 V / m).

Given

Formula:

Solution:

Issue 8

What is the potential difference between two points with a distance of 6000 cm, taken on a single voltage line in a homogeneous electric field with a voltage of 2 V / m? (Answer: 120 V).

Given

Formula:

Solution:

Issue 9

What is the field energy in the capacitor if the voltage across the flat capacitor plates is 150 V and the charge is 80 mC? (Answer: 6 mJ).

Given

Formula:

Solution: = 6 mJ Answer: 6 mJ

Issue 10

The flat capacitor received a charge of 2 mC and a field energy of 0,5 mJ. What was the capacitance of the capacitor? (Answer: 16 mF).

Given

Formula:

Issue 11

When a flat capacitor was charged at 4 · 10−5 C, its energy was 20 mJ. What was the voltage between the capacitor plates? (Answer: 1000 V).

Given

Formula:

Solution:

Issue 12

Find the energy density of the electric field at a point with dielectric constant 4 and voltage 3 · 103 V / m. (Answer: 159 mJ / m3).

Given

Formula:

Solution:

Test questions on the completion of Chapter VII

1. How much electrostatic force (N) affects a 800 mC charge at a point with a field strength of 5 V / m?

2. A) 4 · 10-2; B) 4 · 10−3; C) 3,2 · 10−5; D) 1,6 · 10−5.

2. What is the acceleration (m / s27,3) of an electron moving in an electric field with a voltage of 2 kV / m? me = 9,1 · 10−31 kg.

3. A) 4,8 · 1016; B) 4,8 · 1015; C) 7,2 · 1016; D) 9,6 · 1015.

3. A charged drop with a mass of 1 · 10−4 g is in equilibrium in a homogeneous electric field with a voltage of 100 N / C. Determine the charge of the drop (C).

4. A) 10−8; B) 10−6; C) 10−4; D) 10−3.

4. A metal sphere with a radius of 2 cm was charged with 1,2 nC. Find the electric field strength near the surface of the sphere (kV / m).

5. A) 27; B) 18; C) 24; D) 9.

5. A metal sphere with a radius of 6 cm is charged with 24 nC. What is the voltage at a point 3 cm from the center of the sphere (kV / m)?

6. A) 45; B) 90; C) 60; D) 0.

6. On the surface of a sphere with a radius of 12 cm, a positive charge of 0,18 mC is evenly distributed. Find the field potential at the center of the sphere (V).

7. A) 90; B) 60; C) 120; D) 180.

7. How does the potential energy of their interaction change if we reduce the distance between two point charges by a factor of 9?

8. A) increases 9 times; B) decreased by 9 times;

9. C) increases 3 times; D) Decreased by 3 times.

8. When a point q charge is moved between two points with a potential difference of 100 V, 5 mJ of work is done. q What is the magnitude of the charge (mC)?

9. A) 20; B) 5; C) 500; D) 50.

S	1	2	3	4	5	6	7	8
J	B	B	A	A	D	—	A	D

Exercise 8

Issue 1

The EYUK of the battery was 1,55 V. When it was connected to an external resistor with a resistance of 3 Ō, the voltage at the battery terminals was 0,95 V. What is the internal resistance of the battery?

Given

Formula:

Solution:

Issue 2

The current in the circuit connected to the EYuK 30 V battery is 3 A. The voltage across the battery terminals is 18 V. Find the internal resistance of the battery and the external circuit resistance.

Given

Formula:

Solution:

Issue 3

When the power supply was connected to a 5 5 resistor, the current in the circuit was 2 A, and when connected to a 8 qarshilik resistor, the current in the circuit was 3 A. Find the internal resistance of the source and EYuK (Answer: 40 Ō; XNUMX V).

Given

Formula: Solution:

 bunda

Issue 4

EYuK of the current source element 1,5 V. Short circuit current 30 A. What is the internal resistance of the element? If the element is connected to a coil with a resistance of 1 Ō, what is the voltage across the poles of the element?

Given

Formula:

Solution:

Issue 5

If the external resistance connected to the battery increases n times and the voltage across the resistor increases from U1 to U2, what is the EYuK of the battery? (Answer: E = U1 U2 (n – 1) / (U1n - U2)).

Given

Formula:

Solution:

Issue 6

Under what conditions can the voltage at the ends of the battery be greater than its EYuK?

Answer: When the current flows in reverse

Issue 7

Elements EYuK E1 and E2 are connected in parallel. If their internal resistances are equal, find the potential difference in the element clamps.

Issue 8

Elements with EYuK 1,5 V and 2 V are connected with the same signal poles. A voltmeter connected to the battery terminals showed a voltage of 1,7V. Find the ratio of the internal resistances of the elements (Answer: r1 / r2 = 2/3).

Given

Formula:

Solution:

Issue 9

The internal resistances of the elements with EYuK 1,3 V and 2 V are 0,1 Ō and 0,25 Ō, respectively. They are connected in parallel. Find the current in the circuit and the voltage at the terminals of the elements.

Given

Formula:

Solution:

Issue 10

The voltmeter has four measuring limits: 3, 15, 75, 150 V. The current that can pass through the instrument is 0,8 mA. If the internal resistance of the voltmeter is 1000 Ō, find the additional resistors R1, R2, R3 and R4 connected to it (Answer: 9,49,249 and 499 kŌ).

Given

Formula: Solution:

Issue 11

A galvanometer with an internal resistance of 200 Ō turns on the whole scale when the current is 100 μA. What kind of resistance can be connected to it in series, acting as a voltmeter and measuring up to 2V?

Given I

Formula:

Solution:

Test questions on the completion of Chapter VIII

 

1. In what unit is the electromotive force of a current source expressed?

2. A) N; B) J; C) A; D) V.

3. EYUK of the source 12 V. How many joules of external forces does the 50 C charge inside the source do when moving from one pole to another?

4. A) 60; B) 50; C) 330; D) 600.

5. Who was the first to create the classical theory of electrical conductivity of metals?

6. A) P. Drude and Dutch igi zigi H. Lawrence; B) ER Siemens;

7. C) K.Rikke; D) T. Stewart and R. Tolman.

8. How is the shunt connected to the ammeter selected and connected?

RA is the resistance of the ammeter, r is the shunt resistance.

1. A) RA> r, connected in parallel; B) RA> r, connected in series;

2. C) RA

3. How is the additional resistor connected to the voltmeter selected and connected? Rv is the voltmeter resistance, r is the additional resistance.

4. A) Rv> r, connected in parallel B) Rv> r, connected in series

5. C) Rv

6. The electrical circuit consists of a resistor with a resistance of 4 Ō and a current source of EYuK 12 V with an internal resistance of 2 Ō. How many volts is the voltage drop across the resistor?

7. A) 8; B) 2; C) 4; D) 12.

8. Fill in the blanks. ta .. by connecting n elements, the total EYuk n times when the battery is formed ……

9. A)… increases… successively; B)… decreases in series…;

10. C)… consecutive… does not change; D)… parallel… increases.

11. The total EYuK ilganda when the battery is formed by connecting n elements ……, the internal resistance n times…

12. A)… parallel… does not change… decreases;

13. B)… parallel… increases… decreases;

14. C)… parallel… does not change; increases;

15. D)… consecutive… does not change… decreases.

16. When a current source with an internal resistance of 0,01 Ō was short-circuited, the current was 1000 A. Find the source EYuK (V).

17. A) 10; B) 9; C) 12; D) 15.

10. An external resistor of 2 Ō is connected to a battery with an internal resistance of 50 Ō. If the EYUK of the battery is 12 V, find the FIK (%).

11. A) 92; B) 89; C) 96; D) 100.

S	1	2	3	4	5	6	7	8	9	10
J	D	D	A	D	C	A	A	A

Exercise 9

Issue 1

How does the temperature of a copper rod change when a current of density 0,5 A / mm9 passes through it for 2 s? The specific resistance of copper is 1,7 · 10–8 Ō · m, z ich l ig i 89 0 0 kg / m 3, specific heat capacity is 380 J / (kg K)

Answer: 0,20 oC).

Given j c = 380 J / kg K

Formula:

Solution:

Issue 2

How many times does the specific resistance of a niobium coil change when heated to 100 o C? For niobium a = 0,003 K – 1 (Answer: 1,3 times).

Given

Formula:

Solution:

Issue 3

The resistance of the nickel wire at 20 oC was 20 Ō. What is its resistance if it is heated to 120 oC? For nickel a = 0,0001 K – 1.

Given

Formula: Solution:

Issue 4

In a vacuum diode, the electron reaches the anode at a speed of 8 Mm / s. Find the anode voltage (Answer: 180 V).

Given

Formula:

Solution:

Issue 5

In a vacuum diode, the maximum current at the anode was 50 mA. How many electrons fly out of the cathode every second? (Answer: 3,1 · 1017).

Given

Formula:

Solution:

Issue 6

Is there a difference between a positive ion and a cavity in semiconductors?

Answer: The place where the hollow electron leaves is an atom with a positive ion cavity

Issue 7

For some reason, the number of free charge carriers in a semiconductor does not change, although the electron-cavity pair is formed continuously without changing the external conditions.

Answer: Because they exchange places in electronic cavities

Issue 8

What kind of conductivity is formed when phosphorus, zinc, potassium are added to germanium?

Answer:

Issue 9

Why is the current at the same p-junction at the same voltage much larger than the current at the reverse junction? Answer: When P + is connected to n, the direction of the internal and external field is the same, and the field contains more charged particles.

Issue 10

A 1 k qarshilik resistor was connected in series to the end of the thermistor (a semiconductor device whose resistance varies with temperature) and was supplied with a voltage of 20 V. At room temperature, the current in the circuit was 5 mA. When the thermistor was immersed in hot water, the current flowing through it remained at 10 mA. How many times has the thermistor resistance decreased? (Answer: 3 times).

Given R = 103Ω U = 20V I1= 5 mA I2= 10 mA

Solution:

Test questions on the completion of Chapter IX

1. Fill in the blanks. The phenomenon of electrons escaping from metals due to heating is called….

2. A)… thermoelectric emission…; B). ..electron emission…;

3. C)… output case…; D)… saturation current….

4. What is the nature of electric current in a vacuum?

5. A) one-way movement of electrons;

6. B) one-way movement of positive ions;

7. C) one-way movement of the flow of man fi y ions;

8. D) consists of one-way motion of electrons, positive and negative ions.

9. What type of conductivity do donor compound semiconductors have?

10. A) mainly electronic conductivity;

11. B) mainly perforated permeability;

12. C) equal amounts of electron and hole conductivity;

13. D) does not conduct electricity.

14. A current of 1 mA flows through a pure semiconductor due to the orderly motion of electrons. What is the total current flowing through the semiconductor?

15. A) I mA; B) 2 mA; C) 0,5 mA; D) 0.

16. Keep talking. "Resistance of a semiconductor with increasing temperature…"

17. A)… increases; B)… first increases, then decreases;

18. C)… decreases; D)… decreases first, then increases.

19. What happens when a hole and an electron meet in a semiconductor?

20. A) positive ion; B) neutral atom; C) man fi y ion; D) positive and negative ions.

7. What particles are associated with the conductivity of the mixture?

8. A) mainly free electrons;

9. B) mainly pits;

10. C) equal amounts of free electrons and cavities;

11. D) different amounts of free electrons or cavities.

8. “Sealing layer in a semiconductor at the right p-point…” Continue.

9. A)… expands;

10. B)… narrows;

11. C)… remains unchanged;

12. D)… varies linearly with magnitude.

9. How many electrons are involved in a covalent bond?

10. A) 1 ta; B) 2 ta; C) 3 ta; D) 4 ta.

10. At what signal potential is applied to the base of an n – p – n type transistor with respect to the emitter?

11. A) positive; C) zero;

12. B) man fi y; D) It does not matter what sign it is given.

S	1	2	3	4	5	6	7	8	9	10
J	A	A	A	B	C	B	C	B	B	A

A SET OF PROBLEMS FOR INDEPENDENT SOLUTION

MECHANICS

1. The machine is half the time c₁= 60 km / h, and in the remaining half c₂ = Walking at a speed of 30 km / h. Find the average speed?

    Solution:

2. The car is halfway all the way c₁= 50 km / h, and in the remaining half c₂ = 10

    walking at a speed of km / h. Find the average speed?

   Solution:

3. As the boat moves steeply to shore at a speed of 3.6 km / h, the current flows through it

    180 m downstream. If the width of the river is 600 m, how much is the boat

    What is the time elapsed and the flow rate?

   Given: v = 3.6 km / h = 1m / sec

                   s = 180 m

                   L = 600 m

                   t = ?, v₁=?

   Solution:,

4. From a height of h = 30 m the rock began to fall without initial speed. Last 0.05 sec

    How many times did you walk inside?

   Given: h = 30 m

                   Dt = 0.05 sec

                   v₀ =0

                    Dh =?

   Solution:,,

,

5. From a height of h = 25 m the rock began to fall without initial speed. How long did it take to cover the last 0.5 m of road?

   Given: h = 25 m

                   DH = 0.5 m

                   v₀ = 0

                    Dt =?

   Solution:,,,

6. The car was coming at a speed of 36 km / h. After the engine was switched off, it slowed down and stopped within 40 sec. How far did the car travel in those 40 seconds?

   Given: c₀ = 36 km / h = 10 m / sec

                    t = 40 sec

                    v = 0

                     s =?

   Solution:,,

7. The horizontally shot object moved for 2 sec and landed at a distance of 24 m. From what height was the body shot? v_x what is the speed

   Given: t = 2 sec

                     s = 24 m

                      h =? , v_x =?

   Solution:,,

8. To the horizon a the velocity of an object shot at an angle c₀  if, and if the movement time t = 4 sec, then from there  h climbed to a height?

 Given: t = 4 sec, g = 10 m / sec²

                  ----------

                    h =?

 Solution: Rise and fall times are equal:

              , So h

              falls from a height without initial velocity:

9. What is the acceleration of the aspiration to the center if the stone at the end of a 0.8 m long rope is rotated at a linear speed of 4 m / sec?

   Given: R = 0.8 m

                       v = 4 m / sec

                      ------

                         a=?

    Solution: Acceleration of an object moving in a straight line in a circle toward the center

10. The rotating disk speed is 24 m / sec. Center the points on the edge of the disk

      the acceleration of the aspiration is 120 m / sec² . What is the diameter of the disc?

     Given: v = 24 m / sec

                        a = 120 m / sec²

                        ------

                          D =?

       Solution: Do not center the points on the edges in a circular motion

                   acceleration, where R = D / 2 is the radius of the disk. - on the edge of the disk

The linear velocity of the points, it is equal to the speed of movement of the disk :.

                   So,

11. A load of mass m = 4 kg is hung on the rope. Find the tensile strength of the rope (g = 10 m / sec²):

       if a) The strip is facing upwards a= 2 m / sec² acceleration

       if b) Looking down the strip a= 3 m / sec² acceleration

   Given: m = 4 kg, g = 10 m / sec²

1. a) up a= 2m / sec² b) facing down a= 3m / sec²

                  —————————————————————

1. in cases a) and b) T =?

   Solution: When the rope is still, its tensile strength is equal to the weight of the load T₀= mg.

              Tension force as the thread accelerates upwards increases   T_a= mg + ma= m (g +a) = 48 N

               Tension force as the thread accelerates downward decreased  T_b= mg- ma= m (g-a) = 28 N

12. If the rope can withstand a maximum tension of 3 kN, with what acceleration of a load of 200 kg

      lifting so that the rope does not break (g = 10 m / sec²  )

        Given: m = 200 kg, g = 10 m / sec²

                   T = 3 kN = 3000 N

                  --------

                       a =?

   Solution: If the rope accelerates upwards, it is the force of tension increases :, henceforth,

13. How much force must a 10-ton stationary wagon weigh on it in order to travel 20 m in 15 seconds with a flat accelerating motion? Ignore friction.

   Given: m = 10 t = 10000 kg

                   t = 20 sec, s = 15 m, v₀ = 0

                  -------------

                       F =?

   Solution: The road in a smooth accelerating motion, the acceleration from it

                 . Hence, F = ma= m * 2s / t² = 10⁵* 2 * 15/400 = 7500 N

14. A rubber ball of mass 0.2 kg comes at a speed of 5m / sec and is perpendicular to a hard and flat board

       elastic hit and returned without losing speed. How many pulses did the board receive?

       Given: m = 0.2 kg

                       v = 5 m / sec

                     -----

                         =?

       Solution: From the law of conservation of momentum: Impulses before and after exposure

                      The difference is transmitted to the board:

15. The wagon reduced its speed from 2 m / s to 6 m / s in 2 s. Wagon

       What is the angle of the load on the ceiling? (g = 10 m / sec²)

Given: t = 2 sec, g = 10 m / sec²

                       v₂ = 6 m / sec

                       v₁ = 2 m / sec

                       -----

Solve:

The tensile strength of the rope is due to the T - weight mg and the inertial forces:, the projections of this equation on the X and Y axes:, and. These are:. So,,,

16. The body with the horizon is a = 30^o li standing on a sloping plane. What is the value of the coefficient of sliding friction?

Given: a = 30^o

                  ----

                    k_s =?

Solve:

The force of resistance is directed in the opposite direction (upwards) to the movement. The force that moves the body is the force of gravity mg  is equal to the projection of the X axis:. Hence, the condition of action:. In addition,

17. 1 J of work was performed when lifting a load of mass 2 kg with an acceleration to a height of 80 m. At what acceleration did the load rise?

Given: m = 1 kg

                 h = 2 m

                 A = 50 J

                 -----

                    a =?

Solve:

The force acting on the lift with acceleration. So, the work done. From:

18. Increasing the speed of a 3 ton mass load at a distance of 20 m from 2 m / s to 8 m / s

      How much work is required for? Sliding friction force 1 N. (g = 10 m / sec² )

Given: m = 3000 kg, g = 10 m / sec²

                  s = 20 m

                  v₁ = 2 m / sec, v₂ = 8 m / sec

                  F_s = 1N

                 -----------

                  A =?

Solve:

In the absence of friction, the work done would increase the kinetic energy of the load:, but in the case of friction, it must also be overcome:

19. If the velocity of a nucleus with a mass of 5000 kg coming out of the mouth of a 5 kg ball is 100 m / s, what is the "kicking" speed of the ball?

Given: m₁ = 5000 kg

                 m₂ = 5 kg

                  v₂ = 100 m / sec

                --------

                  v₁ =?

Solve: The system is stored full pulse:, hence:

20. How much higher will a rubber ball falling from a height of 5 m hit the ground and rise again?

      Recovery coefficient (v.)₂/v₁ = 0.8).

Given: h₁ = 5 m

                  k = v₂/v₁ = 0.8

                -------

                  h₂ =?

Solve:

the potential energy at the drop is converted to kinetic energy, and the kinetic energy at the return is converted to potential energy, according to which part of the energy is lost c₂<v₁ . From the ratio of equations:, Hence

MOLECULAR PHYSICS

1. Water density r = 10³ kg / m³, if the molar mass is M = 18 g / mol, determine the amount of substance in 3 liters of water.

   Given: r = 10³  kg / m³

                   M = 18 gr / mol = 18 × 10^-3 kg / mol

                   V = 3 liters = 3 × 10^-3м ³

                 -----------

                    n =?

   Solution: The amount of substance is mol

2. The ideal gas pressure in the vessel is 80 kPa. If the average kinetic energy of 1 molecule10^-20If J, what is the concentration of the molecules?

   Given: p = 80000 N / m²

                   = 10^-20 J

                 -------

                    n =?

   Solution:

   The ideal gas pressure can be expressed as:. In addition,

3. 10⁰What is the RMS velocity of hydrogen gas molecules at temperature C?

     Hydrogen molecule molar mass M = 2 gr / mol. R = 8.31 J / (mol × K) universal gas constant

   Given: t = 10⁰C, T = 283 K

                   M = 2 × 10^-3 kg / mol

                   R = 8.31 J / (mol × K)

                 ---------

                         v_kv =?

   Solution:

   The average square velocity of ideal gas molecules

4. The temperature of 37 kg of iron at 5 ° C is given by the amount of heat of 300 kJ

      how much will it cost see for iron. heat capacity c = 450 J / (kg * K).

     Given: t₁ = 37⁰C, T₁ = 310 K

                       m=5kg

                       Q = 300 kJ = 3 × 10⁵ J

                      ----------

                          t₂ =?

     Solve:

     Given the amount of heat, the body temperature increases:, hence,

     , t₂ =T₂ - 273 ≈170.3⁰C

5. Nitrogen temperature of 8 liters at a pressure of 12 MPa 17⁰C. What is the mass of nitrogen?

    Molar mass of nitrogen M = 0.028 kg / mol, R = 8.31 J / (mol × K)

     Given: p = 8 × 10⁶ N / m²

                     V = 12 × 10^-3 m³

                      t = 17⁰C, T = 290 K

                    M = 0.028 kg / mol, Molar mass of nitrogen

                    R = 8.31 J / (mol × K)

                   ---------

                         m =?

    Solution:

     From the ideal gas state equation:,. So:

6. There is 10 kg of gas in a metal cylinder and the pressure is 10⁷ N / m² was. At constant temperature

    The more mass of gas escapes, the pressure is 2,5 × 10⁶ N / m²  will remain?

        Given:  m₁= 10 kg

                         p₁ = 10⁷ N / m²

                         V = const, T = const

                         p₂ = 2,5 x 10⁶ N / m²

                         R = 8.31 J / (mol × K)

                       ---------

                         m₁–M₂ =?

         Solution:

     From the ideal gas state equation:,, these are the ratios,

    , or,, So,,

7. 17⁰At a temperature of C, 96000 N / m² at a pressure of 10 m³ gas substance in a volumetric cylinder

     how much R = 8.31 J / (mol × K)

     Given: t = 17⁰C, T = 290 K

                       p = 96000 N / m²

                      V = 10 m³

                      R = 8.31 J / (mol × K)

                     ---------

                         m =?

    Solution:

     From the ideal gas state equation:, the amount of substance, therefore,

8. Mass 0.012 kg gas 7⁰At a temperature of 0.004 m³ occupies the volume. Gas

     density when heated at constant pressure is 0.6 kg / m³ became What a gas

     heated to room temperature?

     Given: m = 0.012 kg

                       t₁ = 7⁰C, T₁= 280 K

                      V₁ = 0.004 m³

                       p = const

                       r₂ = 0.6 kg / m³

                     ---------

                           t₂ =?

    Solution:

    From the ideal gas state equation: In the initial state (1), when heated

     (2) or à (2). Of these, equations (1) (2)

    relative, So,

       t₂ = 1127⁰C

9. At a pressure of 200 kPa, the volume is 60 m³ What is the internal energy of the gas?

         Given:   p = 200 kPa

                           V = 60 m³ 

                             U =?

          Solution:   ,,

10. What is the internal energy of 10 kg of helium when the temperature increases by 0.4 K.

    will change? R = 8.31 J / mol * K, M = 4 g / mol

          Given: DT = 10 K

                          m=0.4kg

                          R = 8.31 J / mol * K

                         M = 0.004 kg / mol

                       --------

                            DU =?

       Solution:

       The internal energy of an ideal gas can be written as:

            ,,,,

11. How much work is done on the gas if 4 kJ of heat is given to the gas in the isothermal process

      will be done?

        Given:  Q = 4 kJ

                          -----

                             A =?

        Solution:In an isothermal process, the heat transferred to the system is used for work.

12. What does it do when 0.32 kg of oxygen is heated to 10 K isobar? (M = 0,032 kg / mol,,)

   Given: m = 0.32 kg

                     DT = 10 K

                      M = 0,032 kg / mol

                          Univ. gas constant

                    ------------------

                        A =?

    Solution: In an isobaric process, the heat transferred to the system is used to increase the internal energy and to work at constant pressure. Bunda

                 work done.

                 Since the ideal gas is from the equation of state,,

                . So,

13. When a gas is given 6 kJ of heat, its internal energy increases by 4 kJ. On the gas

    how much work has been done

Given:   Q = 6 kJ

                   DU = 4 kJ

                   -----

                       A =?

Solve  According to the 1st law of thermodynamics. In addition,

14.Agar gas at 17 ° C 29 l  What volume does it occupy at 27 ° C?

     The pressure was constant.

Given:  t₁ = 17 ° C, T₁ = 290 K

                    V₁ = 29L

                     t₂ = 27 ° C T₂ = 300 K

                  ----------

                       V₂ =?

Solution:The pressure does not change in the isobaric process.

              . So,

15. At 17 ° C, the gas pressure in the metal cylinder was 620 kPa. What is the pressure of a gas when it is heated to a temperature of 37 ° C?

    Given:  t₁ = 17 ° C, T₁ = 290 K

                         p₁ = 620 kPa

                         t₂ = 37 ° C T₂ = 310 K

                       ----------

                            р₂ =?

    Solution:The volume does not change in the isochoric process.

                 . So,

16. A horizontal force of at least 3.8 mN is required to move a stick standing on the surface of the water. How long is the print? (surface tension coefficient for water s = 0.076 N / m)

     Given:  F = 3.8 * 10^-3 N

                          s = 0.076 N / m

                         -------

                              l =?

     Solution: In order to move, you have to overcome the force of surface tension (just like overcoming the force of friction). In addition,

17. At what height does the alcohol rise in a capillary with a radius of 0.4 mm?

     (r = 800 kg / m for alcohol³, s = 0.022 N / m, g≈10 m / sec² )

    Given:  r = 0.4 mm = 4 × 10^-4 m   

                        s = 0.022 N / m

                         r = 800 kg / m³

                       --------

                            h =?

    Solution:

18. 0,2 × 2 on a rod 10 cm in diameter⁸ N / m² How much force must be pressed along its axis to generate mechanical stress?

     Given:  d = 0,2 cm = 2 × 10^-3 m   

                          s = 2 × 10⁸  N / m²

                        --------

                              F =?

     Solution:Stergen log cutting face,

                  So,

19. How much heat is needed to completely melt 0.2 kg of tin at the melting point ?. (specific melting point of tin l = 60 kJ / kg)

     Given:   m=0.2kg

                           l = 60 kJ / kg

                        -------

                              Q_e =? 

     Solution:

20. Length 2 m and cross-sectional area 3 mm² The wire has a force of 150 N.

     under the influence of 1 mm. Determine the voltage generated in the wire and the Yung module.

1. A) 10⁹ Pa, B) 10¹¹ N / m², C) 0.2 * 10¹⁰ Pa, D) 3 * 10⁸ N / m²

     Given:  S = 3 mm² = 3 x 10^-6 m²

                          l = 2 m

                          F = 150N

                         Dl = 1 mm = 10^-3 m

                         ---------

                              E =? 

      Solution:Tension, Relative elongation,

                  Of these, the Yung module.

ELECTRICITY

1. Two-point charge in air (e₁= 1) Affected at a distance of 8 cm. These charges

   in oil (e₂= 5.25) how far to stand to be affected by such force

   do you need

Given: e₁= 1, r₁= 8 cm, e₂=5

               ----------

                r₂ =?

Solution: Conditionally, the Culon forces are equal in both cases :. From:,,,

2. q₁=q₂= q The distance between charges is multiplied by 4 and the value of charge q is 2 times

      How many times does the strength of the Culon effect change if it is gained?

Given: q₁=q₂= q, à 2q

                r à 4 r

               ------

                F₂/F₁ =?

Solution: Culon forces:,, hence,, decreased by 4 times

3. The box contains a capacitor of 30 pF and 70 pF capacitors. How many capacitors of any capacitance can be connected in parallel to produce a capacitance of 330 pF?

Given: C1 = 30 pF

                   C2 = 70 pF

                   C = 330 pF

                    m = ?, n =?

Solution:If the capacitors are connected in parallel, the capacitances are added.

            There are two unknowns in the problem, and the equation is one. From this

             . m, n are positive integers, m> 0 to n <33/7 »5.

            n = 3,6,9… v.x satisfies the n = 3 problem condition. So,

            We find n = 3 and m = 4: C₁= 30 pF and 4 ta, C₂= 70 pF and 3 ta.

4. The capacitances of the capacitors connected in the figure are C₁= 50 pF, C₂= 25 pF, C₃If = 40 pF, what is the total capacitance?

Given: C₁ = 50 pF

                   C₂= 25 pF

                   C₃= 40 pF

                  ------

                     C_mind =?

Solution:C₁   and C₂  connected in parallel, they are added :. Andy C₁₂  and C₃ Because they are connected in series:. So,

5. What is the total resistance of the shema?

   Solution:,

6. The distance between 2 identical balloons is 20 cm. They are equally negatively charged and repel with a force of 1 mN. How many extra electrons are in each bubble?

       Given: r = 20 cm = 0,2 m

                         F = 1 mN = 10^-3 N

                         q_e = 1,6 * 10^-19 C

                         k = 9 * 10⁹  N * m²/C²

                      ----------

                          n =?

       Solution: From the pendant law,

                      ta

7. Two metal spheres are positively charged and one is charged 2 times less than the other.

    The balloons were flattened against each other and pushed back to the previous distance. How many times has the force of interaction changed?

        Given: q₁= 2q, q₂=q

                       ------

                         F₂/F₁ =?

Solution: In the first case. In the second case, in each (see₁+q₂) / 2 = 1.5q and

will be zayad.

So, F₂/F₁ = 9 / 8≈1.12 times

8. The 10 and 40 nC charges are 12 cm apart. 3 charge

    how far away from the first is it in balance?

    Given: q₁= 10 nC

                       q₂= 40 nC

                       r = 12 cm

                    ------

                         x =?

    Solution: (3) 1-charge force, 2-charge force

    To stay in balance, both forces must be equal: F₁=F₂ .

    In addition,

9. How many times will the resistance change if the uninsulated conductor is bent 3 times?

    Given: l¹=l / 3,  S¹=3S,

    Solution: Decreased by 9 times

10. Cutting surface 1.4 mm² If a current of 1 A flows through the aluminum wire, then the field strength

      how much (Aluminum: r = 0.028 × 10^-6 W × m)

    Given: I = 1A, r = 0.028 × 10^-6 W × m

                     S=1.4mm² = 14 x 10^-7 m²

                     ----------

                           E =?

     Solution:

11. In the picture a from the chain b  Ammeter when the circuit is switched on

      How much does the indicated current change? In both cases

      The voltage is the same.

      Solution: a- state total resistance 3R, Current I_a= U / 3R

                   b- in case R / 2 + R = 3R / 2, Tok I_b = 2U / 3R, I_b/I_a= Increases by 2 times

12. Find the total capacitance if capacitors 160 pF, 40 pF, 300 pF are connected in parallel?

 Given: C₁ = 160pF

                   C₂= 40 pF

                   C₃= 300pF

                  ------

                     C_p =?

 Solution:Total capacitance when different capacitors are connected in parallel.

             So, C_p = 500pF

13. A 6 nC charge in a liquid dielectric is a field voltage of 3 kV / m at a distance of 20 cm

      forms. What is the absorbance of the dielectric? (k = 9 * 10⁹ N * m²/C²  )

  Given: E = 2 * 10⁴ V / m

                   r = 0.03 m

                   q = 6 * 10^-9 C, k = 9 * 10⁹ N * m²/C²

                  ------

                     e =?

   Solution:, hence,

14. Electronic speed 10⁷ m / sec and 3 * 10⁷ electric field to increase m / s ek

      What should be the potential difference? (e / m = 1.76 * 10¹¹ C / kg)

     Solution:,

15. The bulb passed a charge of 20 C at a certain time and did 130 J of work. What is the voltage across the bulb?

Given:q = 20 C

                  A = 130 J

                   U =?

Solution: Work from now on

OPTICS AND ATOMS

1. Is the light falling at an angle of 45 ° from the vacuum to the transparent plate? A break

    If the angle is 30 °, find the plate refractive index.

Given:a = 45 °,

                   b = 30 °

                  ----

                    n  = ?

Solution:From the law of refraction of light

2. The beam of light passes from the transparent plate (n =) to the vacuum. Full interior

    at what angle the light inside the plate to return

    should fall?

Given:n=

                 ----

                    a₀=?

Solution:Tula internal return limit angle. From this, a₀= 45⁰ 3. Refractive index of light 1 medium  n₂=An angle of 1,2 ° to the 2nd medium, which is 45

    a full internal return begins to be observed when it falls below. 1 breaking of the medium

    indicator n₁ find the

Given: n₂ = 1.2

                  a₀ = 45 °

                 ----

                    n₁ =? 

Solution:Tula internal return limit angle. In addition,

4. How far away from the lens is the image of an object placed 8 cm away from the lens with a focal length of 10 cm?

Given:F = 8 cm

                   d = 10 cm

                 ----

                     f =?

Solution:Lens formula. From this,.

5. Determine the mass of all the protons of the helium atom. (m_p= 1.67 * 10^-27 kg)

Given:He, Z = 2

                  m_p= 1.67 * 10^-27 kg

                  -------

                   M_{p, He} =?

Solution: The mass of atomic protons depends on the nuclear charge Z: M_{p, Z} = Z * m_p . So,

              M_{p, He} = 2 * 1.67 * 10^-27 kg = 3.34 * 10^-27 kg

6. Find the mass of the nucleus of the oxygen isotope. (m_p ≈ m_n = 1.67 * 10^-27 kg)

Given:m_p ≈ m_n = 1.67 * 10^-27 kg

Solution:The mass of the nucleus is approximately! ”Masses of all nucleons (mass number A)

             equal to the sum, m≈A * m_p , So,

                  , A = 15, m () = 15 * 1.67 * 10^-27 kg ≈25 * 10^-27 kg

7. Find the mass of the isotope nucleus of uranium (m_p ≈ m_n = 1.67 * 10^-27 kg).

   Given:m_p ≈ m_n = 1.67 * 10^-27 kg

   Solution:The mass of the nucleus is approximately! ”Masses of all nucleons (mass number A)

                equal to the sum, m≈A * m_p , So,

                  , A = 235, m () = 235 * 1.67 * 10^-27 kg = 392,45 * 10^-27 kg

8. Light glass so that the angle of refraction is 2 times smaller than the angle of incidence

    at what angle to the surface? ( n = 1.6 Glass)

       Given: b  = a / 2

                        n = 1.6 Glass

                      --------

                         a =?

       Solution: The law of refraction, Hereafter

9. What is the focal length of a lens with an optical power of 10 dptr?

         Given: D = 10 dptr

                         ------

                            F =?

          Solution:

10. If the light from one of the stars reaches in 300 years, it is from Earth

      What is the distance to the star?

     Given:t = 300 * 365 * 24 * 3600 sec

                       c = 3 * 10⁸ m

                        -----

                            s =?

     Solution:s = c * t = 28.5 * 10¹⁷ m

11. Find the total charge of protons in the helium atom. (q_p = 1.6 * 10^-19 C)

      Given:q_p = 1.6 * 10^-19 C

                         -------

                            Q_p =?

      Solution:, Z = 2, Q_p = Z * q_p = 3.2 * 10^-19 C

12. Suppose a rocket is flying at the speed of light at an altitude of 100 km along the equator of the Earth. A rocket flying at this speed orbits the Earth many times in 1 s. The radius of the Earth is 6400 km.

       Given: h = 100 km

                           t = 1 sec, R = 6400 km

                           s = 3 × 10⁵ km / sec

                          -------

                            n =?

       Solution:The length of the 1st rotation is C = 2p (R + h), the total path pressed is L = ct. Hence the number of revolutions, n ≈ 7 times

13. The light is transferred to the glass so that the refracted light is perpendicular to the reflected light (n = 1.6)

      at what angle should it fall?

       Given: b  = 180^o - a - 90^o  = 90^o - a, out of shape

                        n = 1.6 Glass

                      --------

                         a =?

       Solution: The law of refraction,

                     henceforth.

14. If the refractive indices of diamond and glass are 2.42 and 1.5, what should be the ratio of the thicknesses of the plates so that the light scattering times are the same on the plates made of them?

       Given:  n₁ = 2.42

                        n₂ = 1.5

                      -----

                         d₂/d₁ =?

       Solution: n = c / v, v = c / n, t = d / v = dn / c, hence d₁n₁/ c = d₂n₂/ c or d₂/d₁ = n₁/n₂ = 1.61

15. a is what the particle consists of

16.  Who found the law?

17. Why do protons in the nucleus not escape due to Coulomb repulsion?

18. How many neutrons are there in a hydrogen atom?

19. What is the number of Z protons and N neutrons in the nucleus with the “mass number” A?

      connected?

        A = Z + N

20. What is the number of protons and electrons in a lithium atom?

      3 protons 3 electrons