3 . B —Impulse equals the change in momentum. Because the mass of the cue ball remains the same
during the collision, the impulse will be in the direction of the change in velocity. J = Δp = Δ(mv = m
(Δv ). The change in velocity is best described by choice B.
4 . A —Conservation of momentum gives us the following:
Note that we need to subtract the mass of the ordnance from the combined mass (M ) after it has been
fired from the jet.