A railroad car (m = 3000 kg) is coasting along a level track with an initial speed of 25...

A railroad car (m = 3000 kg) is coasting along a level track with an initial speed of 25 m/s. A load of coal is then dropped into the car as sketched in Figure 7.19. (a) Treat the railroad car plus coal as a system. Is the momentum of this system along the horizontal (x) or vertical (y) conserved? (b) What are the velocities of the car and the coal before the collision along the direction found in part (a)? (c) Express the conservation of momentum condition for the system. (d) If the final speed of the car plus coal is 20 m/s, what is the mass of the coal?

(reference figure 7.19)