Q26 of 48 Page 45

A body falls towards earth in air. Will its total mechanical energy be conserved during the fall? Justify.

As we know that gravitation is conservative force;

Therefore, mechanical energy of the body falling towards


earth in air will be conserved.


More from this chapter

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24

A body is being raised to a height h from the surface of earth. What is the sign of work done by

(a) applied force


(b) gravitational force?


 25

Calculate the work done by a car against gravity in moving along a straight horizontal road. The mass of the car is 400 kg and the distance moved is 2m.

 27

A body is moved along a closed loop. Is the work done in moving the body necessarily zero? If not, state the condition under which work done over a closed path is always zero.

 28

In an elastic collision of two billiard balls, which of the following quantities remain conserved during the short time of collision of the balls (i.e., when they are in contact).

(a) Kinetic energy.


(b) Total linear momentum? Give reason for your answer in each case.