Question

You're on a train that's moving forward at 50 mph. You throw a ball in the direction that the train is moving. Relative to you and the train, the ball leaves your hand travelling at 20 mph.From the point of view of someone standing alongside the tracks, how fast is the ball moving?

Answer 1

`Velocity = 70mph`

Explanation:

Given

`Train = 50mph`

`Ball = 20mph`

Required

How fast is the ball seem to be moving?

This question illustrates relative velocity;

Since the ball and the train moves in the same direction, the required velocity relative to the person standing behind is:

`Velocity = Train + Ball`

i.e. we add both velocities

`Velocity = 50mph + 20mph`

`Velocity = 70mph`