Q1. If mass of a body is quadrupled and velocity is made half, then the kinetic energy remains same
- True
- False
- Q2. Work done by a body is
- always negative
- always positive
- always zero
- negative, positive or zero
- Q3. A car of mass 50 kg starting from rest with a final velocity of 40 m/s travels for 20 seconds. What will be the acceleration and the work done to bring it to rest?
- 1.5 m/s2 , 0.4 x 105 J
- 2.0 m/s2 , 4.0 x 105 J
- 2.0 m/s2 , 0.4 x 105 J
- 1.5 m/s2 , 4.0 x 105 J
- Q4. The energy consumed by an appliance rated 1 kW in one hour is 1 kW.
- True
- False
- Q5. What is the unit for work done?
- Pascal
- Joule
- Newton
- Ampere
- Q6. In which one of the following cases is work scientifically said to be done?
- Mira studies for her exam
- Manish pulls the trolley up to a certain distance
- Manoj pushes the wall with no change in the position of wall
- Mitiksha standing at a bus stop holding a bag in her hand.
- Q7. Water jet of an area of cross-section 2 cm2 strikes the wall normally with a velocity of 20 m/s and falls freely. The magnitude of force exerted on the wall is (Density of water = 1000 kg m-3)
- 40 N
- 60 N
- − 80 N
- 100 N
- Q8. A fish weighing 35 kg dives and hits the ground (zero height) with kinetic energy equal to 3500J. Find the height through which the fish dived. (Take g = 10 m/s2)
- 100 m
- 10 m
- 20 m
- 1 km
- Q9. In which one of the following ways elastic potential energy of an object can be achieved?
- Raising the body to a height
- Setting the object in motion
- Using an elastic band to tie the object
- Compressing or stretching the object
- Q10. 1 joule is the energy required to do 1 joule of work.
- True
- False
Q11. Which one of the following is possessed by a freely falling body during its fall?- Kinetic energy
- Potential energy
- Sound energy
- Both kinetic energy and potential energy
- Q12. A boy climbs onto a wall that is 3.4 m high and gains 2250 J of potential energy. What is the mass of the boy? Take g = 9.8 m/s2
- 50 kg
- 67.5 kg
- 62.5 kg
- 70 kg
- Q13. If displacement and force are in opposite directions, work is considered to be negative.
- True
- False
- Q14. A body is lifted directly and a second body is lifted along a curved path to same height. Yet they have same potential energy.
- True
- False
Q15. A 500 kg cloth bag is pulled up a smooth plane 6 m long to a platform which is 4 m above the ground. The work done is (Take g = 10 ms-2)- 2 x 102 J
- 2 x 103 J
- 2 x 104 J
- 2 x 105 J
- Q16. If energy remains same at all the points, then potential energy at the top is same as potential energy at the bottom.
- True
- False
- Q17. A 1kW hair dryer is used for half an hour. How much energy is used?
- 1 unit
- 0.5 unit
- 1.5 unit
- 0.05 unit
- Q18. A body of mass 4 kg has a momentum of 20 kg m/s, its K.E. is
- 25 J
- 50 J
- 70 J
- 100 J
- Q19. For an object to have gravitational potential energy only, it must be
- Falling
- Moving
- At an elevated position with respect to the ground
- Accelerating
- Q20. Activities like playing in a field, talking with friends, humming a tune, watching a movie, attending a function are considered to be work.
- True
- False
- Q21. A body at rest cannot have
- Potential energy
- Kinetic energy
- Electrical energy
- Both A and B
- Q22. A body of mass 44 kg is moving at a velocity of 10 m/s is brought to rest in 10 minutes, the work done is
- 22 J
- 220 J
- -2200J
- 22000 J
- Q23. If the velocity of a moving car is halved, its kinetic energy would
- Remain same
- Double
- Become Half
- Become one-fourth
- Q24. Power of a body is how fast or slow work is done by that body.
- True
- False
- Q25. 1 J is the energy required to do ____ of work.
- 1 N
- 1 J
- 9.8 N
- 98 J
- Q26. A passenger carrying the load on his head & standing at a place & wondering. No work is done.
- True
- False
- Q27. As a body falls from a height, its potential energy increases and kinetic energy decreases.
- True
- False
- Q28. Two bodies of masses m and 4 m are moving with equal kinetic energy. The ratio of velocities with which they are traveling is
- 1:2
- 2:1
- 3:4
- 4:5
- Q29. A body of mass 5 kg moving with an acceleration of 5 ms-2 gets a displacement of 2m, the work done by the force is
- 25 J
- 50 J
- 75 J
- 100 J
- Q30. Calculate the distance between a man and a box when 100 J of work done to move the box with a force of 15 N.
- 16.6 m
- 26.6 m
- 6 m
- 6.6 m
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