If you flip a fair coin 7 times, what is the probability that you will get exactly 2 tails?

What happens when an acid dissolves?

Neils bohr believed that electrons orbited the nucleus in different energy levels, based on strong support from

A40 kilogram skier starts at the top of a 12 meter high slope. at the bottom, she is travelling 10 meters per second. how much energy does she lose to friction