If the force required to move the rock at a distance of 9 feet is 80 lbs, what would be the force required with a distance of 15 feet?

Question

Explain your thought process.

The Rock Is On A Fulcrum

Answer 1

Hi Donovan,

When an object is on a fulcrum, force varies inversely with distance. Meaning the closer the object is to the fulcrum, the more force required to move it. Use the equation F=k/x as a model for how an object's force required relates to its distance. k is the constant that can be used for this fulcrum no matter the distance of the object from the fulcrum. We find this constant and then plug it into the equation when distance = x = 15 feet.

F = k/x

80 = k/9

k = 720

F = 720/15 = 48 lbs