A1,000-kg vehicle traveling 4 m/s eastward collided with another vehicle, at which point it moved 1 m/s westward. what was the vehicle's change in momentum?
a. 1,000 kg • m/s
b. 3,000 kg • m/s
c. 4,000 kg • m/s
d. 5,000 kg • m/s

22. the top of a cliff is located a distance h above the ground. at a distance h/2 there is a branch that juts out from the side of the cliff, and on this branch a bird's nest is located. two children throw stones at the nest with the same initial speed, one stone straight downward from the top of the cliff and the other stone straight upward from the ground. in the absence of air resistance, which stone hits the nest in the least amount of time?