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: ...

Forgive me for all the posts on ESPN's Sport Science (example: Pulling and Power). I can't help myself. In the short episode recently, Sport Science compared a football player pulling a sled with huge ...

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 ...