A ball is released from rest at the top of an inclined plane, whose length is d = 140 cm. It takes the ball t1 = 0.70 s to roll down to the bottom of the plane. (a) What is the ball's acceleration down the plane?

(b) A second run is performed. This time, just as the ball is released from the top, another ball is rolled up the plane from the bottom. The two balls collide exactly halfway along the ramp. How much time passes between the top ball's release and the collision? (Hint: consider the initial position and the final position of the top ball.)

(c) What was the initial speed of the bottom ball? (Hint: the two balls have the same acceleration down the plane.)