A 103-kg baseball player slides into second base. The coefficient of kinetic friction between the player and the ground is ìk = 0.729. (a) What is the magnitude of the frictional force? (b) If the player comes to rest after 1.27 s, what is his initial speed?

Answer 1

weight = 103 (big guy!) * 9.81 = 1010 N

F = .729 * 1010 = 737 N

F = m a
-737 = 103 a
(negative because stopping)

a = - 7.15

v = Vi + a t
0 = Vi -7.15 (1.27)
Vi = 9.08 m/s