A steel ball is rolling along a 20-inch long straight track so that its position, measured from the midpoint of the track, is d = 3 sin(t) inches after t seconds have passed. (Think of the track as aligned from left to right. Positive positions mean the ball is to the right of the center; negative positions mean it is to the left.) a) Find a formula for the velocity of the ball after t seconds. What is happening when the velocity is positive? when it is negative? when it equals zero? Write a sentence or two describing the motion of the ball. b) How far from the midpoint of the track does the ball get? How can you tell? c) How fast is the ball going when it is at the midpoint of the track? d) Does it ever go faster than this? How can you tell