Two students in bumper cars want to prove conservation of momentum. They collide their bumper cars. The first bumper car has a mass of 120 kg and was moving with a velocity of 4 m/s before the collision and with a velocity of −2 m/s after the collision. The second bumper car has a mass of 90 kg and was moving at a velocity of −5 m/s before the collision. To prove conservation of momentum, what must the velocity of the second bumper car be after the collision?
A. 1.0 m/s
B. 2.7 m/s
C. 3.0 m/s
D. 2.3 m/s
