Two people are sitting on wheeled chairs 1 metre apart. Person A is holding a 2kg ball. Person A throws the ball to Person. What happens to person A? Explain. a.) their chair stays still
b.) chair rolls backwards
c.) chair rolls forwards

B - Person A's chair rolls backwards.

Explanation:

This can be seen simply through the Conservation of Momentum. When the ball is thrown to be, the ball's momentum(+m) is transfererd to B, so B's chair moves forward(think about it - it makes sense, doesn't it?), meaning A's chair moves backwards.

So, B.

EXTRA TIP: Try drawing a diagram to help you!