Suppose you catch a baseball and then someone invites you to catch a bowling ball with either the same momentum or the same kinetic energy as the baseball. Which would you choose? Explain.

Solution 2DQ The momentum of a body is given by p = mv , where m is the mass of the body and v is the speed. 1 2 The kinetic energy of the body is given by K = m2 Let the mass of the baseball be m and its speed be v. So, its momentum p = mv Kinetic energy k = mv 2 2 Let the mass of the bowling ball be M and let its velocity be V. So, its momentum P = MV 2 Kinetic energy K = MV2 Momentum: Given, mv = MV m V Therefore, the speed of the baseball is more than that of the bowling ball. If mass of the bowling ball is say, 10 times more than that of the baseball, its speed will be 1/10 th that of the baseball. Kinetic energy: If k = K 2 2 2mv = MV 2 mv = MV 2 We know, M > m, then v > V But in the expression for kinetic energy velocity is squared. Therefore, the baseball will have more kinetic energy than the bowling ball even though the latter is heavier. Therefore, you should choose to catch the balls with same m omentum.