A potter forms a piece of clay into a right circular cylinder. As she rolls it, the height h of the cylinder increases and the radius r decreases. Assume that no clay is lost in the process. Suppose the height of the cylinder is increasing by 0.2 centimeters per second. What is the rate at which the radius is changing when the radius is 3 centimeters and the height is 5 centimeters? A baseball diamond is a square with sides of length 90 ft. A batter hits the ball and runs toward first base with a speed of 21 ft/s.

At what rate is his distance from second base changing when he is halfway to first base?
Answer = ft/s

At what rate is his distance from third base changing at the same moment?
Answer = ft/s