A boy stands at the end of a train that is collapsing at 60 km / h, throwing a ball back at a speed of 30 km / h.

A boy stands at the end of a train that is collapsing at 60 km / h, throwing a ball back at a speed of 30 km / h. in which direction the ball will move relative to the observer.

Given:

v1 = 60 km / h – train speed;

v2 = 30 km / h – the speed of the ball, in the direction opposite to the movement of the train.

It is required to determine the speed of the ball v3 and its direction relative to a stationary observer on the ground.

The train path moves in the positive direction and the ball moves in the negative direction. Then, since the ball and the train move in different directions, the speed of the ball relative to a stationary observer will be:

v3 = v1 – v2 = 60 – 30 = 30 km / h, direction – in the direction of the train.

Answer: With respect to a stationary observer, the ball will move in the direction of the train at a speed of 30 km / h.