posted by Jordan .
A boy is standing on a skateboard holding two 5.0 kg bowling balls. Initially they are moving to the left at a speed of 3.0 m/s. At one point the boy throws one ball to the right at 4.0 m/s causing his speed to increase. Before he can slow down, he throws the second ball to the right at 4.0 m/s. If the boy and the board have a mass of 45 kg, what is the velocity immediatly after throwing the second ball?