Non-uniform Circular Motion 4. The figures show the centripetal acceleration vector, a c, at four successive points on the trajectory of a particle moving in a counterclockwise circle. a. For each, draw the tangential acceleration vector, a t, at points 2 and 3 or, if appropriate, write a = 0. b. Determine if the particle is speeding up or slowing down. N 2 3 3 3