Chapter 11: Work and Energy

Multiple Choice Questions Test

Time: 30 Minutes

Max Marks: 20

Questions: 20

Instructions:

• This test contains 20 multiple-choice questions.
• Each question has only one correct answer.
• Choose the best answer for each question.
• Take g = 10 m/s² where required unless specified otherwise.

1. In which of the following situations is work done, according to the scientific definition?

A student studying for 3 hours.

A man pushing against a stationary wall.

A coolie carrying a load on his head and moving on a horizontal platform.

A child pulling a toy cart through a distance.

2. The SI unit of work is:

Watt

Newton

Joule

Pascal

3. A force of 10 N acts on an object and displaces it by 2 m in the direction of the force. What is the work done?

5 J

20 J

0.2 J

200 J

4. What is the angle between the force of gravity and the displacement of an object moving on a horizontal plane?

0°

45°

90°

180°

5. A body of mass 2 kg is lifted to a height of 5 m. Calculate the work done against gravity. (Take g = 10 m/s²)

10 J

50 J

100 J

0 J

6. A man carries a load of 50 kg on his head and walks 10 m on a horizontal road. The work done by the man is:

500 J

5000 J

250 J

0 J

7. The kinetic energy of an object of mass 2 kg moving with a velocity of 3 m/s is:

KE = ½ × m × v²

3 J

6 J

9 J

18 J

8. The potential energy of a body of mass 2 kg at a height of 10 m (g = 10 m/s²) is:

PE = m × g × h

20 J

100 J

200 J

400 J

9. The law of conservation of energy states that:

Energy can be created but not destroyed.

Energy can be destroyed but not created.

Energy can neither be created nor destroyed.

Energy can be created and destroyed in equal amounts.

10. Power is defined as:

The ability to do work.

The rate of doing work.

The product of force and displacement.

The energy stored in an object.

11. The commercial unit of electrical energy is:

Joule

Watt

Kilowatt-hour

Newton

12. A force of 5 N acts on an object at an angle of 60° to the direction of displacement. If the displacement is 4 m, the work done is:

W = F × s × cosθ

10 J

20 J

5 J

17.32 J

13. A car is moving with a constant velocity. The net work done by the forces acting on the car is:

Positive

Negative

Zero

Cannot be determined

14. Which of the following has the greatest kinetic energy?

A 2 kg object moving at 3 m/s

A 3 kg object moving at 2 m/s

A 1 kg object moving at 4 m/s

A 4 kg object moving at 1 m/s

15. A spring is compressed. The energy stored in the spring is:

Kinetic energy

Potential energy

Thermal energy

Chemical energy

16. A body is falling freely under gravity. Which of the following remains constant?

Kinetic energy

Potential energy

Total mechanical energy

Momentum

17. The power of a motor that does 600 J of work in 10 seconds is:

Power = Work / Time

60 W

600 W

6000 W

6 W

18. If the velocity of a body is doubled, its kinetic energy becomes:

Double

Half

Four times

Eight times

19. A ball is thrown vertically upwards. At the highest point, its:

Kinetic energy is maximum

Potential energy is minimum

Kinetic energy is zero

Total energy is zero

20. A machine does 200 J of work in 10 s. What is its power?

2 W

20 W

200 W

2000 W

Test Results

Your Score: 0/20