Humans have been making fire by friction for centuries, but it's not easy. Cyndi Monaghan/Moment via Getty Images Fire by friction is a testament to human ingenuity, contributing to the development of ...

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 ...

Friction is hard to predict and control, especially since surfaces that come in contact are rarely perfectly flat. New experiments demonstrate that the amount of friction between two silicon surfaces, ...

You know that two surfaces mate, but what is a friction clutch or brake? Using friction has been the most popular way to engage and stop loads since the 1800s. Surfaces interact with ...