Question

A train car is rolling down the tracks at a speed of 15.0 m/s when it connects with a second car that is initially at rest. If the first car has a mass of 1250 kg and the second is 3270 kg, what will be the combined speed after they connect?

Answer 1

To find the combined speed of the train cars after they connect, we can use the principles of conservation of momentum. The momentum of an object can be calculated by multiplying its mass by its velocity. When the cars connect, their momenta must be equal and opposite, so the final momentum will also be 18750 kg·m/s. The combined velocity is 4.15 m/s.

Step-by-step explanation:

To find the combined speed of the train cars after they connect, we can use the principles of conservation of momentum. The momentum of an object can be calculated by multiplying its mass by its velocity.

Since the second car is initially at rest, its momentum is zero. The momentum of the first car is 1250 kg x 15.0 m/s = 18750 kg·m/s.

When the cars connect, their momenta must be equal and opposite, so the final momentum will also be 18750 kg·m/s.

To find the combined velocity, we can divide the final momentum by the combined mass of the cars.

The combined mass is 1250 kg + 3270 kg = 4520 kg. Therefore, the combined velocity is 18750 kg·m/s / 4520 kg = 4.15 m/s.