A softball of mass 0.220 kg that is moving with a speed of 4.0 m/s (in the positive direction) collides head-on and elastically with another ball initially at rest. Afterward the incoming softball bounces backward with a speed of 1.8 m/s.

Question

a) Calculate the velocity of the target ball after the collision.
b) Calculate the mass of the target ball.

Answer 1

initial momentum = .22*4 = .88 kg m/s =final
initial Ke =(1/2).22(16) = 1.76 J = final

final momentum = .88=.22(-1.8) + m v
final Ke =1.76 = (1/2).22(1.8^2) + .5 m v^2

solve two eqns for m and v