Conservation of Energy and Power

Question

A 259 kg crate slides 3.5 m until coming to a stop after being pushed by a large man. The effective coefficient of kinetic friction between the crate and the surface is 0.18. Calculate the work done by friction

Answer 1

The work W is the product of the applied force F and the distance d. I assume all the motion was horizontal.

F = μmg

W = Fd = μmgd = (0.18)(259)(9.8)(3.5) joules = ? joules

Strictly speaking, W should have a negative sign since it opposes the direction of motion.