I Didn’t Know That

Q: If I am inside a car traveling 35 mph and I throw a ball up inside the car, how come the ball doesn’t smack the back window? If I throw it up from outside the windows, the ball is lost.

A: The car, the air inside it, and the ball are all traveling at the same speed, so the ball comes back down into your hand. If you are in a convertible or throw it up outside the window, however, it encounters air that is not moving and resistance from the air slows the ball and makes it appear to fall backward. The same phenomenon occurs on a larger scale when you stand on the ground and throw a ball into the air. Although the Earth is rotating at 17 miles per second, the air is rotating at the same speed, so the ball comes back down in your glove.