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 ...

Friction is an intrinsic physical phenomenon to curling. Without it, objects in motion would move endlessly, without slowing down. This would cause many safety-related problems: Cars or trains could ...

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 ...

Students explore frictional force through investigations using a scooter. Students explore frictional force through investigations using a scooter and different types of small ramps. Mrs. Norris will ...

In general, friction between two macroscale surfaces is proportional to normal force. However, the frictional characteristics of nanoscale surfaces cannot be fully described by the framework of ...

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 ...