Collar a starts from rest at t = 0 s and moves downward with a constant acceleration of 7 in./s2 . collar b moves upward with a constant acceleration, and its initial velocity is 8 in./s. knowing that collar b moves through 20 in. between t = 0 s and t = 2 s, determine (a) the accelerations of collar b and block c, (b) the time at which the velocity of block c is zero, (c) the distance through which block c will have moved at that time