A ramp 20 feet long rises 4 feet. Ignoring friction, what force is needed to push a 500 pound load up it?

Correct answer to question 85 (Mechanical Comprehension): 100 pounds

Method

The mechanical advantage is length over height, 20 / 4 = 5, so the force needed is 500 / 5 = 100 pounds. The work is unchanged: 100 pounds over 20 feet equals 500 pounds over 4 feet.