How does a pulley system achieve a mechanical advantage?

Question

How does a pulley system achieve a mechanical advantage?

Answer 1

By going back and forth with the rope/cable across a pulley system you are multiplying the force from pulling on the rope by that many times.

In return, you have to pull that much more rope to move it. So, the rope might be half as hard to pull (require 1/2 the force to pull it), but you'll have to pull twice as much length of rope as the thing will move.

Answer 2

When you consider all the loops around the pulley, eah strand is holding its fraction of the weight. The mechanical advantage of a pulley is equal to the number of strands going around the pulley system. It does not include the one strand that changes the direction of the pull.

Answer 3

Its simple,

When you start pulling the rolling action takes place so the friction is not much, by this way we can easily lift weights lesser than ours...