2.5. A train car is sitting on a level track when a second car moves in. The second car hits the first, their hitches engage, and they move together. Both cars have equal masses of about 120 000 kg, and the second car initially has a velocity of 1.5 m/s. (a) Draw a diagram that illustrates the situation and include an arrow representing the velocity vector of the second car and a separate arrow representing , the unit vector for the coordinate system along the tracks. (b) Write vector expressions for both the velocity and momentum of the second car before the collision. (c) Show that, if the only momentum transfer involved is between the two train cars, their final speed will be 0.75 m/s. (d) Is all of the kinetic energy lost by the second car transferred to the first car? If not where else does it go?