We know the weight of the baseball player, his initial speed, his final speed, and the coefficient of friction. First we will find the force of friction acting on the player by finding the normal force. The force of friction is the only one acting in the horizontal plane, so it can be equated to the mass times the acceleration of the player sliding. Once we have the acceleration, the rest is just plugging it into an equation of motion with constant acceleration.
d could also be found using:
