At t=0, Ball 1 is rolling up a ramp and Ball 2 is released from the top of the same ramp. The balls don't collide. Which velocity vs. time graph at right best represents the motion of the two balls?
[Figure: Shows velocity-time graphs labeled A, B, C, D with different curve patterns]
A) A
B) B
C) C
D) D
E) Both A & D