| Class | 9th |
| Subject | Science |
| Chapter 10 | Work and Energy |
| Question Type | Tick the correct option |
Tick the correct option
1. Which of the following is the scientific conception of work?
(A) Physical effort put into a task
(B) Achieving the desired result
(C) Force applied on an object to change its position
(D) Effort required to complete a task
Correct Answer: C
2. What is the unit of work?
(A) Watt
(B) Newton
(C) Joule
(D) Ohm
Correct Answer: C
3. No work is done when an object moves
(A) along the direction of force
(B) opposite to the direction of force
(C) at any angle to the direction of force
(D) at 90° to the direction of force.
Correct Answer: D
4. In case of negative work the angle between the force and displacement is
(A) 0°
(B) 45°
(C) 90°
(D) 180°
Correct Answer: D
5. A girl is carrying a school bag of 3 kg mass on her back and moves 200m on a levelled road. The work done against the gravitational force will be (g =10 ms–2)
(A) 6 ×103 J
(B) 6 J
(C) 0.6 J
(D) zero
Correct Answer: D
6. Which of the following is an example of work?
(A) Moving a book from one table to another
(B) Holding a book stationary in your hand
(C) Pushing against a wall that does not move
(D) Lifting a book and keeping it at the same height
Correct Answer: A
7. A ball of mass 1 kg thrown upwards reaches a maximum height of 5.0 m. Calculate the work done by the force of gravity during this vertical displacement
(A) – 59 J
(B) – 49 J
(C) – 30 J
(D) – 48 J
Correct Answer: B
8. A horse does a work of 6250 J while applying a force of 250 N in pulling a tonga. The displacement produce in tonga is
(A) 12.5 m
(B) 15 m
(C) 25 m
(D) 20 m
Correct Answer: C
9. The work done by a pendulum after complete oscillation is
(A) zero
(B) equal to potential energy of the pendulum
(C) equal to kinetic energy of the pendulum
(D) equal to total energy of the pendulum
Correct Answer: A
10. A uniform force of 4N acts on a body of mass 40 kg for a distance of 2.0 m. The kinetic energy acquired by the body is
(A) 4 × 2 × 2 J
(B) 4 × 4 × 2 × 108 erg
(C) 4 × 2 J
(D) 4 × 4 × 2 erg
Correct Answer: C
11. Which one of the following is one of the possible units of energy?
(A) Watt
(B) Newton second
(C) Newton
(D) kWh
Correct Answer: D
12. According to the law of conservation of energy,
(A) Energy cannot be created but can be destroyed
(B) Energy can be created but cannot be destroyed
(C) Energy can be created and destroyed
(D) Energy can neither be created nor destroyed, only transferred or converted
Correct Answer: D
13. When work done by force of gravity is negative
(A) PE increases
(B) KE increases
(C) PE remains constant
(D) PE decreases
Correct Answer: A
14. A body is falling from a height h. After it has fallen a height h/2, it will possess
(A) only potential energy
(B) only kinetic energy
(C) half potential and half kinetic energy
(D) more kinetic and less potential energy
Correct Answer: C
15. An aeroplane flying at a height of 20,000 m at a speed of 300 kmh–1 has
(A) only potential energy
(B) only kinetic energy
(C) both, potential and kinetic energy
(D) none of the above
Correct Answer: C
16. One horse-power is equal to
(A) 746 watt
(B) 726 watt
(C) 736 watt
(D) 756 watt
Correct Answer: A
17. What is the rate at which work is done called?
(A) Power
(B) Energy
(C) Force
(D) Velocity
Correct Answer: A
18. Power required to perform 100 J of work in 5 sec,
(A) 10 watt
(B) 20 watt
(C) 30 watt
(D) 40 watt
Correct Answer: B
19. Water stored in a dam possesses
(A) Potential energy
(B) Electrical energy
(C) Kinetic energy
(D) None of the above
Correct Answer: A
20. An iron sphere of mass 10 kg has the same diameter as an aluminium sphere of mass is 3.5 kg. Both spheres are dropped simultaneously from a tower. When they are 10 m above the ground, they have the same
(A) acceleration
(B) momenta
(C) potential energy
(D) kinetic energy
Correct Answer: A