A small glider is coasting horizontally when suddenly a very heavy piece of cargo falls out of the bottom of the plane. You can neglect air resistance. Just after the cargo has fallen out, which of the following correctly describes the horizontal speeds of the plane and the cargo? a. The horizontal speed of the plane goes up and that of the cargo goes down.
b. The horizontal speed of the plane goes down and that of the cargo goes up neither the cargo nor the plane change their horizontal speeds.
c. The horizontal speeds of both the plane and the cargo go down.
d. The horizontal speeds of both the plane and the cargo go up.