Question

A weight lifter lifts a weight off the ground and hold it up then which is correct?

a) work is done in lifting as well as holding the weight
b) no work is done in both lifting and holding the weight
c) work is done in lifting but no work is required in holding
d) no work is done in lifting the weight but work is required to be done in holding

Answer 1

Answer:

a is the correct option

Answer 2

Work is done in lifting but no work is required in holding.

Explanation:

The work done by an object depends on the force and the distance covered due to that force. It is given by :

$W=Fd\ cos\theta$

$\theta$ is the angle between force and displacement

When a weight lifter lifts a weight off the ground, the force acting on it is force of gravity and offcourse it will cover some distance. Work will be done. When he holds the object up, then there is no displacement of the weight lifter. Hence, no work is done.

So, the correct statement is (C) "Work is done in lifting but no work is required in holding".

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