Final answer:
A pulley helps transfer mechanical energy by reducing the input force and increasing the output force. The mechanical advantage of a pulley is determined by the number of supporting ropes, with each additional rope increasing the MA.
Step-by-step explanation:
A pulley helps transfer mechanical energy by reducing the input force and increasing the output force. In a pulley system, a flexible rope or belt is looped around a wheel, and when one end of the rope is pulled, it causes the load on the other end to move. This allows the force applied to be spread out over a longer distance, reducing the effort required to lift a heavy load.
The mechanical advantage (MA) of a pulley is determined by the number of ropes or cables supporting the load. Each additional supporting rope increases the MA, making the load feel lighter. For example, a pulley system with two ropes has an MA of approximately 2, while a system with four ropes has an MA of approximately 4.