Question

A dockworker loading crates on a ship finds that a 25-kg crate, initially at rest on a horizontal surface, requires a 72-N horizontal force to set it in motion. However, after the crate is in motion, a horizontal force of 55 N is required to keep it moving with a constant speed. Find the coefficients of static and kinetic friction between crate and floor.

Answer 1

Step-by-step explanation:

Force of static friction = μs x mg

Given force of static friction = 72 N

μs x mg = 72

μs = 72 / mg

= 72 / 25 x 9.8

= .294

Force of kinetic friction = μk x mg

Given force of kinetic friction = 55

μk x mg = 55

μk = 55 / mg

= 55 / 25 x 9.8

= .2245