1.1 What is friction? Take this everyday example: when a coffee mug rests on a flat table, the kinetic frictional force is zero. There is no force trying to move the mug across the table, so there is ...

Most people have experienced the hair-raising effect of rubbing a balloon on their head or the subtle spark caused by dragging socked feet across the carpet. Although these experiences are common, a ...

Scientists developed a new model, which shows that rubbing two objects together produces static electricity, or triboelectricity, by bending the tiny protrusions on the surface of materials. Most ...

EVANSTON, Ill. -- Most people have experienced the hair-raising effect of rubbing a balloon on their head or the subtle spark caused by dragging socked feet across the carpet. Although these ...