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 ...

Work close workEnergy transferred by a force. Work done = force × distance moved in the direction of the force. is done when energy is transferred from one store to another. Work is also done when a ...

Friction is a key phenomenon in applied physics, whose origin has been studied for centuries. Until now, it has been understood that mechanical wear-resistance and fluid lubrication affect friction, ...