This is a classic introductory physics problem. Basically, you have a cart on a frictionless track (call this m 1) with a string that runs over a pulley to another mass hanging below (call this m 2).

How do we know the mass of a planet originally appeared on Quora - the knowledge sharing network where compelling questions are answered by people with unique insights. Answer by Geoffrey Widdison on ...

It's a problem that Albert Einstein identified more than 100 years ago. It's a problem we could be on the cusp of solving, or that could take another century to untangle. And the problem is that we ...

When is a traffic jam not a traffic jam? When it's a quantum traffic jam, of course. Only in quantum physics can traffic be standing still and moving at the same time, say researchers. When is a ...