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#### Work, Energy and Power Two Marks Question

11th Standard

Reg.No. :
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Physics

Time : 00:45:00 Hrs
Total Marks : 30
15 x 2 = 30
1. How can an object move with zero acceleration (constant velocity) when the external force is acting on the object?

2. Why should the object be moved at constant velocity when we define potential energy?

3. Write the differences between conservative and Non-conservative forces. Give two examples each.

4. Define the following
a) Coefficient of restitution
b) Power
c) Law of conservation of energy
d) loss of kinetic energy in inelastic collision

5. A bob of mass m is attached to one end of the rod of negligible mass and length r, the other end of which is pivoted freely at a fixed center O as shown in the figure. What initial speed must be given to the object to reach the top of the circle? (Hint: Use law of conservation of energy). Is this -speed less or greater than speed obtained in the section 4.2.9?

6. Draw a graph showing the variation of potential energy of an object thrown vertically upward by a boy with respect to its height.

7. If energy is neither created nor destroyed, what happens to the so much energy spent against friction?

8. What is the work done by the person in holding 15 kg suitcase while waiting for a bus for 15 minutes?

9. What is the work done by the force of tension in the string of simple pendulum?

10. What are non-conservative forces?

11. Which physical quantities is / are conserved during elastic and inelastic collision?

12. Express a unit of electrical energy in terms of joule.

13. A variable force F = kx2 acts on a particle which is initially at rest. Calculate the work done by the force during the displacement of the particle from x = 0 m to x = 4 m. (Assume the constant k = IN m-2)

14. A light body and a heavy body have the same linear momentum. Which one has greater K.E?

15. An object of mass m is projected from the ground with initial speed v0. Find the speed at height h.