Arailroad handcar is moving along straight, frictionless tracks with negligible air resistance. in the following cases, the car initially has a total mass (car and contents) of 150 kg and is traveling east with a velocity of magnitude 4.60 m/s. find the final velocity of the car in each case, assuming that the handcar does not leave the tracks.

part a : an object with a mass of 21.0 kg is thrown sideways out of the car with a speed of 2.40 m/s relative to the car's initial velocity.
part b : an object with a mass of 21.0 kg is thrown backward out of the car with a velocity of 4.60 m/s relative to the initial motion of the car.
part c : an object with a mass of 21.0 kg is thrown into the car with a velocity of 6.00 m/s relative to the ground and opposite in direction to the initial velocity of the car.