physics
posted by lebohang .
two boys paul mass 60kg and john mass 40kg are standing on skateboards. They place their hands against each other and push away from each other so that they start to move in opposite direction. (a) if paul moves to the left with velocity of 0.8m/s.. Calculate john's velocity

The law of conservation of linear momentum
0 = m1•v1 + m2•v2
v2 = m1•v1/m2 =60•0.8/40=1.2 m/s