Question

Diego 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. Diego pulls 10.5 meters of rope to lift the crate. Which statement is correct?(1 point) Responses Alan will save work by using the compound pulley. Alan will save work by using 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 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 the same amount of force with the compound pulley as he would without it.

Answer 1

To determine the correct statement, we need to analyze how a compound pulley system works. When using a pulley, the mechanical advantage allows one to lift a heavier load with less force.

Here, Diego pulls 10.5 meters of rope to lift the crate a height of 3.5 meters. This indicates that the pulley system has a mechanical advantage. The ratio of the distance pulled to the height lifted is:

\[
\text{Mechanical Advantage} = \frac{\text{Distance pulled}}{\text{Height lifted}} = \frac{10.5 \text{ meters}}{3.5 \text{ meters}} = 3
\]

This means that for every 3 units of distance Diego pulls, the crate is lifted 1 unit of height. Therefore, he uses one-third of the force he would need without the pulley because the mechanical advantage divides the input force needed by that factor.

Thus, the correct statement is:

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