Explain Physics Please.
Ball A of mass 5 kilograms moving at 20 meters per second collides with ball B of unknown mass moving at 10 meters per second in the same direction.
After the collision, ball A moves at 10 meters per second and ball B at 15 meters per second, both still in the same direction. What is the mass of the ball?
The answer would be 10 kg.
But why?? Explain…