The first semester of an undergraduate physics course invariably spends a lot of time on two big ideas: The momentum principle and the work energy principle. Both deal with forces acting on an object, ...

Consider the following physics problem. An object with a mass of 1 kg and a velocity of 1 m/s in the x-direction has a net force of 1 Newton pushing on it (also in the x-direction). What will the ...

When a magnetic material is bombarded with short pulses of laser light, it loses its magnetism within femtoseconds (10 –15 seconds). The spin, or angular momentum, of the electrons in the material ...

Why does light carry energy even though it has no mass? This video explains the real physics behind photons, energy–momentum ...

It's impossible to talk about football these days without talking about the problem of big hits. The giant dramatic collisions between players moving at high speed are at once one of the great ...

When you shine a flashlight into a glass of water, the beam bends. That simple observation, familiar since ancient times, hides one of the oldest puzzles in physics: what really happens to the ...