When a soccer ball is kicked toward a player and the player deflects the ball by "heading" it, the acceleration of the head during the collision can be significant. Figure 2-38 gives the measured acceleration a(t) of a soccer player's head for a bare head and a helmeted head, starting from rest. At time t = 7 .0 ms, what is the difference in the speed acquired by the bare head and the speed acquired by the helmetedhead?

200 100 Helmet t (ms) a (m/s)