10 A6 kg mass moving at 10m/s collides with a 4 kg mass moving in the
same direction at 4 m/s. After the collision both the 6 kg and 4 kg mass
continue to move in the same direction. If the 4 kg mass is moving at
10m/s, what is the speed of the 6 kg mass? *

The drag force, fd, imposed by the surrounding air on a vehicle moving with velocity v is given by fd = cdaρv 2/2 where cd is a constant called the drag coefficient, a is the projected frontal area of the vehicle, and ρ is the air density. an automobile is moving at v = 80 kilometers per hour with cd = 0.28, a = 2.3 m2, and ρ = 1.2 kg/m3.