Question

Why is the mechanical advantage of using a single pulley always 1? Assume there’s no friction. A. The input force is in a different direction than the output force. B. The input force is less than the output force. C. The input force is greater than the output force. D. The input force is equal to the output force.

Answer 1

D. The input force is equal to the output force

Explanation:

A pulley changes the direction of the applied force, but does not change its magnitude. The mechanical advantage is the ratio of output force to input force, so must be 1 when the force magnitude does not change.