Alan will use a compound pulley to lift a crate from the floor of his garage to a storage shelf. The shelf is 3.5 meters above the floor. Alan pulls 10.5 meters of rope to lift the crate. Which statement is correct?

Question

Alan will use a compound pulley to lift a crate from the floor of his garage to a storage shelf. The shelf is 3.5 meters above the floor. Alan pulls 10.5 meters of rope to lift the crate. Which statement is correct?
Responses

Alan uses one-third the force he would have needed without the compound pulley.

Alan uses three times the force he would have used without the compound pulley.

Alan uses the same amount of force with the compound pulley as he would without it.

Alan will save work by using the compound pulley.

GPT-4o mini · Answer

The correct statement is: **Alan uses one-third the force he would have needed without the compound pulley.** Explanation: In a compound pulley system, the distance you pull the rope is greater than the height the load is lifted. In this case, Alan pulls 10.5 meters of rope to lift the crate 3.5 meters. This means that the mechanical advantage of the pulley system is 10.5 m / 3.5 m = 3. Therefore, Alan is able to lift the crate using one-third the force he would have needed without the pulley.