# MCQs on Work Done by Constant Force

**MCQs on Work Done by Constant Force**

**Q1: If the unit of force and length each be increased by four times, then the unit of energy is increased by **

- 16 times
- 8 times
- 2 times
- 4 times

**Answer: (a) 16 times**

**Q2: A man pushes a wall and fails to displace it. He does**

- Negative work
- Positive but not maximum work
- No work at all
- Maximum work

**Answer: (c)No work at all**

**Q3: When a retarding force is applied to stop a train, the train stops after 80 m. If the speed is doubled, then for the same retarding force, the distance when the train stops would be**

- The same
- Doubled
- Halved
- Four times

**Answer: (d) Four times**

**Q4: You lift a heavy book from the floor of the room and keep it in the bookshelf having a height of 2 m. This process takes 5 seconds. The work done by you will depend on**

- Mass of the book and the time taken
- Weight of the book and height of the bookshelf
- Height of the bookshelf and the time taken
- Mass of the book, height of the bookshelf and the time taken

**Answer: (b) Weight of the book and height of the bookshelf**

**Q5: A body of mass m kg is lifted by a man to a height of one metre in 30 seconds. Another man lifts the same mass to the same height in 60 seconds. The work done by them are in the ratio**

- 1:2
- 1:1
- 2:1
- 4:1

**Answer: (b) 1:1**

**Q6: Which of the following is a scalar quantity**

- Displacement
- Electric field
- Acceleration
- Work

**Answer: (d) Work**

**Q7: A force of 5 N acts on a 15 kg body initially at rest. The work done by the force during the first second of motion of the body is **

- 5 J
- ⅚ J
- 6 J
- 75 J

**Answer: (b) ⅚ J**

**Q8: A force of 5 N, making an angle θ with the horizontal, acting on an object displaces it by 0.4 m along the horizontal direction. If the object gains kinetic energy of 1 J, the horizontal component of the force is **

- 1.5 N
- 2.5 N
- 3.5 N
- 4.5 N

**Answer: (b) 2.5 N**

**Q9: The work done against gravity in taking 10 kg mass at 1 m height in 1 sec will be **

- 49 J
- 98 J
- 196 J
- None of these

**Answer: (b) 98 J**

**Q10: A body of mass 6 kg is under a force which causes displacement in it is given by S = t ^{2}/4 mts where t is time. The work done by the force in 2 seconds is**

- 12 J
- 9 J
- 6 J
- 3 J

**Answer: (d) 3 J**