Question

In an elastic collision, a 480-kg bumper car collides directly from behind with a second, identical bumper car that is traveling in the same direction. The initial speed of the leading bumper car is 4.5 m/s and that of the trailing car is 7.2 m/s.

Hint

1. Assuming that the mass of the drivers is much, much less than that of the bumper cars, what are their final speeds?
   The speed of the leading bumper car after collision is  m/s, and the speed of the trailing bumper car after collision is  m/s.
2. Assuming that the total mass of leading bumper car is 35% greater than that of the trailing bumper car, what are their final speeds?
   The speed of the leading bumper car (now 35% more massive) is  m/s, and the speed of the trailing bumper car after collision is  m/s.

Answer 1

a)

As the collision is elastic both the momentum and the kinetic energy is conserved.

---(1)

---(2)

From equations (1) and (2), we get,

b)