Question

A man carries a load on his head through a distance of 5m the maximum amount of work is done when he
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Answer 1

Answer:

When the man lifts it vertically upwards. As in this case, he has to move vertically opposite to gravity

Explanation:

Work is done only to the extent that the direction of movement is aligned with the direction of force. That is, the dot product of force and displacement vectors. A load on his head would seem to be directed downwards (gravity)

W = FdcosΘ

So maximum work will be done when cosΘ has maximum value of | 1 |.

So the work done will be maximum if he lifts it at an angle of cos 180 (When the man lifts it vertically upwards) , where he has to do work not only against gravity but also value of cos Θ will be maximum |1|.