Ball b, with a mass of 30kg, is moving to the left at -10 m/s. with what velocity should ball a, with a mass of 10 kg, move to the right and collide with b, so that ball a rebounds with a velocity of -30 m/s, and ball b with velocity of 10 m/s, after the collision? assume the collision to be perfectly elastic. use the formula for perfect elasticity. m1v1(initial) + m2v2(initial) = m1v1(final) + m2v2(final) m1 = mass of object 1, m2 = mass of object 2 v1 = velocity of object 1, v2 = velocity of object 2