Two billiard balls of equal mass collide. Ball 1 is initially moving at 0.43 m/s to the left, and ball 2 is initially at rest. Which of the following sets of final velocities does not describe an inelastic collision between the balls? A. Ball 1 at 0.12 m/s left, Ball 2 at 0.31 m/s left

B. Ball 1 at 0.21 m/s left, Ball 2 at 0.22 m/s left

C. Ball 1 at 0.10 m/s left, ball 2 at 0.33 m/s left

D. Ball 1 at rest, ball 2 at 0.43 m/s left

Distance covered = speed x timethe distance traveled going against the stream = distance traveled with the stream.therefore it is the speed and the time that are the variables.as he travels the same distance both ways, speed x time is the same for each way.going upstream his speed is 4 kph; going downstream his speed is 6 kph.therefore we have two simultaneous equations: time upstream x 4 = time downstream x 6time upstream + time downstream = 60 minutestherefore we have the equation: time upstream = 6/10 hour, time downstream therefore = 4/10 hour.distance traveled at 4km/hr in 6/10 hour = 24/10 = 2.4km.check: distance traveled at 6km/hr in 4/10 hour = 24/10 = 2.4km.