CHAPTER-13, WORK AND ENERGY

1. The kinetic energy of a body decreases by 10%. What is the percentage decrease in momentum?

 
 
 
 

2. An object of mass 2 kg falls from a height of 20 m above the ground. If g = 10 m/s2, the loss of P.E. just before the object strikes the ground is

 
 
 
 

3. Potential energy of your body is minimum when you

 
 
 
 

4. Chlorophyll in plants converts light energy into

 
 
 
 

5. A car weighing 500 kg working against a resistance of 500 N, accelerates from rest to 20 m s-1 in 100 m

 
 
 
 

6. When the force applied and the displacement produced in the body are inclined at 90° with each other, the work done is

 
 
 
 

7. A student carries a bag weighing 5 kg from the ground floor to his class on the first floor that is 2 m high. The work done by the boy is

 
 
 
 

8. The mass of a ball A is twice the mass of another ball B. The ball A moves at half the speed of the ball B. The ratio of the kinetic energy of A to that of B is

 
 
 
 

9. No work is done when

 
 
 
 

10. Ns is equivalent to

 
 
 
 

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