This entry contributed by Dana Romero
One of the fundamental mechanical machines. With a pulley, the amount of work done does not change, but force is traded for distance.
The work W done by a force F acting through a distance s is just
and a pulley lowers the force needed to move an object by some factor n by increasing the distance over which the new force acts, by the same factor,
where n is determined by the number of pulley wheels involved.
The same equation applies to an inclined plane, where the same vertical movement is attained with a lower force acting through a longer distance.
Fulcrum, Inclined Plane, Lever, Screw, Simple Machine
