A tennis player places a 54 kg ball machine on a frictionless surface. The machine fires a 0.057 kg tennis ball horizontally with a velocity of 38 m/s toward the north. What is the final velocity of the machine?

Question

m/s to the south

Answer 1

momentum is conserved.
Massmachine*veloctitymachine=-massball*velocityball

velocitymachine=-.057/54 * 38 North

and of course, -North is South