The damage done by a projectile on impact is correlated with its kinetic energy. Calculate and compare the kinetic energies of
these three projectiles:
a) a 10.0-kg stone at 30.0 m/s
b) a 100.0-g baseball at 60.0 m/s
c) a 20.0-g bullet at 300. m/s

An athlete swings a ball, connected to the end of a chain, in a horizontal circle. the athlete is able to rotate the ball at the rate of 8.13 rev/s when the length of the chain is 0.600 m. when he increases the length to 0.900 m, he is able to rotate the ball only 6.04 rev/s. (a) which rate of rotation gives the greater speed for the ball? 6.04 rev/s 8.13 rev/s (b) what is the centripetal acceleration of the ball at 8.13 rev/s? m/s2 (c) what is the centripetal acceleration at 6.04 rev/s? m/s2