Question

A 40 ton rail car and a 100 ton rail car, initially at rest, are connected together with a giant but massless compressed spring between them. When released, the 40 ton car is pushed away at a speed of 5.0 m/s relative to the 100 ton car. What is the speed of the 100 ton car relative to the 40 ton car?

1) 5.0 m/s
2) 10.0 m/s
3) 20.0 m/s
4) Cannot be determined

Answer 1

The speed of the 100-ton car relative to the 40-ton car is 5.0 m/s.

Step-by-step explanation:

To find the speed of the 100-ton car relative to the 40-ton car, we need to understand the concept of conservation of momentum. In this scenario, the total initial momentum of the system is zero since both cars are initially at rest.

After the release, the 40-ton car moves away at a speed of 5.0 m/s relative to the 100-ton car. This means that the 40-ton car gains momentum in one direction, while the 100-ton car gains momentum in the opposite direction to keep the total momentum of the system zero.

Since momentum is a vector quantity, the speed of the 100-ton car relative to the 40-ton car will be 5.0 m/s in the opposite direction.