# Physics Question Answer Practice Set-3

1. When one body rolls over the other body, then the frictional.
force is called -
Ans: Rolling friction

2. When one body slides over the other body, then the frictional
force is called -
Ans: Sliding friction

3. A flying airplane possesses of -
Ans: Both kinetic & potential energy

4. What is the CGS unit of work -
Ans: Erg

5. If angle work done is more than 90°, then the work will be -
Ans: Positive

6. Positive work means that force is -
Ans: Parallel to displacement

7. If angle work done is less than 90°, then the work will be -
Ans: Negative

8. Negative work means that force is -
Ans: Opposite to displacement

9. If work done has an angle equal to 90°, then the work will be -
Ans: Zero

10. Zero work means that force is -
Ans: Perpendicular to the displacement

11. When a body is moved along a circular path with the help of
a string its work done is -
Ans: Zero

12. What is the SI unit of linear impulse -
Ans: N-s or Kg-m/s

13. Why a cricket player draws his hand back while catching-
Ans: Due to Impulse

14. Why bogies of a train are provided with buffers -
Ans: Due to Impulse

15. Why vehicles like cars, buses and scooters are provided with
shockers -
Ans: Due to Impulse

16. Opposing force in motion is called-
Ans: Friction

17. The electric motor is a device for converting -
Ans: Electrical energy into Mechanical energy

18 How. many types of kinetic friction-
Ans: Two types (Rolling friction & Sliding friction)

19. What is the CGS unit of energy-
Ans: Erg

20. Ho many types of mechanical energy -
Ans: Two types (Kinetic energy & Potential energy)

21. When momentum is doubled the kinetic energy becomes.
Ans: Four times

21. If the momentum of a body is increased by 50 %, its kinetic
energy will increase by -
Ans: 125 %

22. The solar cell is a device for converting -
Ans: Solar energy into Electrical energy

23. Examples of kinetic energy would be -
Ans: A moving car, a charged particle in an electric field, a
stretched rubber band just released etc.

24. Examples of potential energy would be
Ans: A water in dams, a wound spring of a clock, a book
resting on the table etc.

25. The microphone is a device for converting-
Ans: Sound energy into Electrical energy