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 ...

Consider the block shown above supported by feet at A and B that is at rest on a rough floor. A horizontal force P is applied to the right on the block. As the magnitude of P is increased slowly, two ...

Say we consider a simple experiment of balancing a wooden rod on two fingers. The finger on the left, (1), will remain stationary, whereas the finger on the right, (2), will be moved toward the left.

The familiar heat, wear and general grinding to a halt of friction are all caused by what's going on at the microscopic level when two things rub. And down there, even the smoothest surfaces usually ...

At a busy street crossing, people wait for the signal to change. When one person steps out first, others soon follow. Scientists in Amsterdam have found that this same kind of behavior happens at a ...