Some forces are called contact forces because they require objects to touch. One is tension force, found in stretched wires. Another is the force found in a spring. And last are resistive forces: ...

I'll be honest—friction is pretty complicated. Imagine that I have a block of wood sliding on a table. In some way, the atoms on the surface of the wood block are interacting with the surface atoms on ...

As the force F is applied to block C, a pair of friction forces act on the crate at feet A and B. These friction forces create a net counterclockwise (CCW) moment about the crate’s center of mass. In ...

A famous demonstration of the counterintuitive power of friction involves two telephone directories with their pages alternately interleaved. People are then invited to pull the directories apart, a ...