Physics Math

Question

You are helping your friend move a new refrigerator into his kitchen. You apply a horizontal force of 265 N in the positive x direction to try and move the 59 kg refrigerator. The coefficient of static friction is 0.75

What maximum force (in N) do you need to apply before the refrigerator starts to move?

Answer 1

You need to overcome the maximum force of opposing friction, which is μmg, so you need to apply a total horizontal force of 

 

F = μmg = 0.75(59)(9.8) N = 433.65 N

 

If a force 265 N is already being applied, then subtract 265 N from 433.65 N, and that gives the additional force that must be applied in the same direction.