A99.1-kg baseball player slides into second base. the coefficient of kinetic friction between the player and the ground is μk = 0.646. (a) what is the magnitude of the frictional force? (b) if the player comes to rest after 1.36 s, what is his initial speed?

Samir watches a 100-minute movie on his spaceship. maria's spaceshipe flies in the same direction as samir's spaceship but she observes his move to last 125 minutes and his spaceship to be 40 m long. how long does samir observe his own spaceship to be? according to an observer on earth, planet x is stationary. maria and samir depart earth on their spaceships at the same time, each flying at 0.5c. maria flies toward planet x and samir flies in the opposite direction. according to maria, her voyage to planet x takes 9 years. how many years does marias voyage take according to samir?