Pieter picked up a 20-newton book from the floor. Then he passed it to Ahmad, who carried it for 20 meters. How much work did Ahmad do?

Work done to move the block from bottom to top is 400 J

Explanation:

Work is done against gravity here to move the book from floor to the top

So here work done is given as

W = mgH

here we know that

mg = 20 N

also we know that

H = 20 m

so we have

W = 20(20) J

a and b sometimes have a positive value

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