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 ...

Delving into history books, we can learn that already thousands of years ago the Egyptians realized that lubricants like water and oil helped reduce the friction of sledges that moved the heavy stones ...

One type of friction can waste energy even when two perfectly smooth surfaces move against each other, but researchers are getting a handle on how to attenuate or stop it completely ...