A145 g baseball is dropped from a tree 13.0 m above the ground. (a) with what speed would it hit the ground if air resistance was negligible? (b) if it actually hits the ground with a speed of 8.00 m/s, what is the average force of air resistance exerted on it?

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