Primary Resources

Warning: Be aware that HyperPhysics doesn't always indicate the vector nature of certain quantities and expects the reader to know from context if something is a vector. Remember, forces always have a magnitude AND direction and must always be added using vectors.

Openstax textbook section on Friction.

Secondary Resources

Gives a pretty good representation on how to think about friction.

The next two videos, Doc Schuster explains Friction

https://www.youtube.com/watch?v=i90-x5Tbnlc

https://www.youtube.com/watch?v=ZqkV-4rHc4I

https://www.youtube.com/watch?v=IHILOnEW5Qg

Other Resources

A concise definition of friction with proper notation.