# Volleyball on the train

Two trains are moving on parallel rails in opposite directions: the first has speed $$5~\mbox{m/s}$$ and the second has speed $$7~\mbox{m/s}$$. A boy in the second train tosses a ball towards a boy in the first train at the moment they are facing each other. How fast should the first boy run in m/s with respect to the first train so that he can catch the ball?

Details and assumptions

• Neglect the effects of gravity.
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