You have a 10" miter saw, and unbeknownst to you one of the teeth on the blade had come loose. When you were cutting, the tooth flew off the blade. Fortunately, you were wearing appropriate protective gear and you were not injured.

But you are curious now. How fast was that tooth going when it flew off the blade? You can solve this if you know the rotational speed of the blade, which is in the user manual of the miter saw: the blade spins at 5000rpm.