Purpose:Show that the instantaneous velocity of an object executing uniform circular motion is tangent to the circle.
Description:A pool ball is rolled clockwise around the inside of the circular band. When the ball leaves the end of the circular segment it will travel in the direction tangent to the circle at the point where it leaves. Consider placing tape markers on the table or floor and having students predict which direction it will go before performing the experiment. Have them justify their conclusions, then discuss the results afterwards.
Compare D1-30 and D1-32, which show similar effects.