Question

does a coolie carrying load on his head do any work while standing or while moving? If not, why?

Answer 1

no coolie was not doing any work because he was carrying weight which is at 90 degree and we all know that at 90 degree no work is done

Answer 2

Workdone = force × displacement

● If the coolie is standing carrying the load, the displacement is 0. So work done is 0.

● If the coolie is moving, he is applying some force to move in the horizontal direction. Let's say the force is F. and since he is moving, there is some displacement.

So work done in moving case is non-zero. So some work is done by the coolie.

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If you want to find the work done by gravity, then work done will be 0 in both cases as force is at 90° to the displacement.