Menu

Friction and Newton's Laws

Part of the Mechanics section of Coddy's Physics journey. Lesson 18 of 97.

Friction is one more force in Newton's second law:

F−μN=maF - \mu N = ma

With no push, friction alone acts, so the object slows down.

A puck sliding right on ice, the arrow v showing which way: the only force along the ice is friction f to the left, and the acceleration a also points left

No push: friction alone acts along the ice, so a points against v, the way the puck moves, and it slows down.

challenge icon

Challenge

You push a 10 kg10\ \mathrm{kg} crate to the right with 60 N60\ \mathrm{N}, and it slides across the floor. The kinetic friction coefficient is μ=0.4\mu = 0.4. Find its acceleration aa.

Try it yourself

Physics diagram: crate, vec; arrows v

Solve for aa

quiz iconTest yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

All lessons in Mechanics