A pulley system with a mechanical advantage of 4 raises a load 3 feet. How much rope must be pulled through?

Correct answer to question 70 (Mechanical Comprehension): 12 feet

Method

Whatever the system saves in force it charges in distance, so with an advantage of 4 the rope travels four times as far: 3 x 4 = 12 feet. Energy in equals energy out, minus friction.