Please answer the following in full:

The motion of a particle moving along a straight line is described by the position function s(t) = 2t' -21t' + 60t, t 2 0 where t is measured in seconds, and s in metres. a) When is the particle at rest? b) When is the particle moving in the negative direction? c) Determine the velocity when the acceleration is 0. d) At t = 3, is the object speeding up or slowing down