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?(1 point)

Question

Responses

Alan will save work by using the compound pulley.
Alan will save work by using the compound pulley.

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

Answer 1

When using a compound pulley, Alan is able to lift a heavy crate with less force than he would need to apply without the pulley. The key concepts here are mechanical advantage and the relationship between the distance moved by the rope and the height lifted.

In this case, the crate is lifted 3.5 meters, but Alan pulls 10.5 meters of rope. The distance he pulls the rope (10.5 meters) is three times the height he lifts the crate (3.5 meters). This means the mechanical advantage of the pulley setup allows Alan to use one-third of the force he would need without the pulley.

Therefore, the correct statement is:

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