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).

Occasionally there are physics lab demonstrations that I think are pretty awesome but that my students just think are "meh." This is one of those cases. The basic idea in this demo, which I used in my ...

Professional players are an exacting bunch. Many come to a match with enough freshly-strung racquets that they can switch to a new one at every ball change. Or, they might have frames strung at ...