I learned to respect friction, as a phenomenon with many nuances, when I was a graduate student. One day, while teaching a problem session in elementary mechanics, I unwisely invented a new problem to ...

Humans have been making fire using friction for thousands of years, with evidence of its use found in archaeological records across different cultures worldwide. Fire by friction is a testament to ...

Physics and Python stuff. Most of the videos here are either adapted from class lectures or solving physics problems. I ...

Without the force called friction, cars would skid off the roadway, humans couldn't stride down the sidewalk, and objects would tumble off your kitchen counter and onto the floor. Even so, how ...

This article has been updated to include comments from Raymond Goldstein and Patrick Warren. It is a mathematical puzzle that stumped Galileo, but researchers in France think they have discovered how ...