Work, Energy and Power Test Online MCQs

1. If the water falls from a dam into a turbine wheel 19.6 m below, then the velocity of water at the turbines, is (take g = 9.8 m/s²)

2. A particle of mass 10 g is kept on the surface of a uniform sphere of mass 100 Kg and radius 10 cm. Find the work to be done against the gravitational force between them to take the particle far away from the sphere (you may take G = 6.67 x 10⁻¹¹ Nm² /kg²)

3. A vertical spring with force constant k is fixed on a table. A ball of mass m at a height h above the free upper end of the spring falls vertically on the spring so that the spring is compressed by a distance d. The net work done in the process is

4. A body of mass 5 kg has momentum of 10 kg m/sec. When a force of 0.2 N is applied on it for 10 sec, the change in its kinetic energy is

5. A spring 40 mm long is stretched by applying a force. If 10 N force is required to stretch the spring through one mm, then work done in stretching the spring through 40 mm is:

6. A block of mass 10 kg is moving in x-direction with a constant speed of 10 m/sec. It is subjected to a retarding force F = -0. 1x joule/meter during its travel from x = 20 meter to x = 30 meter. Its final kinetic energy will be:

7. If the kinetic energy of the body becomes four times of its initial value, then the new momentum will

8. If the force applied is F and the velocity gained is v, then the power developed is:

9. The kinetic energy of a body becomes four times its initial value. The new linear momentum will be

10. A ball loses 15.0% of its kinetic energy when it bounces back from a concrete wall. With what speed you must throw it vertically down from a height of 12.4 m to have it bounce back to the same height (ignore air resistance)?

11. If the water falls from a dam into a turbine wheel 19.5 m below, then the velocity of water at the turbine is: (take g = 9.8 m/sec²)

12. A bullet is fired form a riffle. If the riffle recoils freely, then the kinetic energy of the rifle will be:

13. A body is allowed to slide down a frictionless track freely under gravity. The track end in a semicircular shaped part of a diameter D. The height (minimum) from which the body must fall so that it completes the circle, is

14. A shell of mass m moving with velocity v suddenly breaks into 2 pieces. The part having mass m/3 remains stationary. The velocity of other part will be:

15. When a ball is thrown up vertically with velocity v₀ it reaches a maximum height of h. If one wishes to triple the maximum height then the ball should be thrown with velocity?