A worker in a warehouse uses a rope passing through some pulleys to lift a heavy crate. The worker exerts a force five times less than the weight of the crate but has to move the rope four times as far as the crate moves. This situation...

Question

A) can happen because the extra distance traveled makes up for the smaller force applied

B) can happen because there is friction in the pulleys so the work done by the worker will not equal the work done on the crate

C) cannot happen because a crate that heavy would lift the worker, rather than the worker lifting the crate

D) cannot happen because the work done by the worker is less than the work done on the crate

I thought the answer was B, but my teacher said that wasn't right. Is it A? I don't think it would be impossible, but I might be wrong.

Answer 1

work done by man: 4h*1/5w=work

work done on crate: h*w=work
w&h = 1

man = 4*.2 = 0.8
crate = 1*1 = 1

So is it D?

Answer 2

Exactly, you figured it out. The man would have to pull farther (more parts in the tackle), like maybe eight times as far at 1/5 the weight