7. A pool cue ball moving at 2.1 m/s east collides in a straight line with the eight ball at rest. Find the velocity of the eight ball after the collision if momentum is conserved and
A. the cue ball stops. (5 points)
B. the cue ball continues on in the same direction at 0.10 m/s. (5 points)
C. the cue ball continues on in the same direction at 0.70 m/s. (5 points)