It's perhaps the second week of your introductory physics course. Your instructor starts talking about friction and writes the following two formulas on the board. Then there is probably some sort of ...

Probably everyone is familiar with the phenomenon: water drops cling to a pane of glass, if it is tilted out of the horizontal plane. Only when a certain angle is reached they slide off. This raises ...

To study fine touch, selecting samples based on how many mechanical instabilities they can form is more predictive than using the friction coefficient, which has been the default choice.

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 ...