How to Measure the Speed of a Tennis Ball

A tennis ball has very little in common with a car. It's more like a rodent. I will put it on the board because we don't know how it's done and we would like to. You've got, almost, you could just video it and then really quickly measure the speed of the ball. Have they got some little man in the audience or something? Yeah, I mean, there'll be someone probably - but not my day's kind of answer is what I mean.