2. Let a position of an object is defined by s(t) = 3t3 – 27t2 + 72t. Where t' is measures in seconds and 's 'in meters.
(i) At what time the object is at rest?
(ii) Find the intervals where the object is moving right to left or left to
right?
(iii) Determine whether the object is speeding up or speeding down
at t = 4.​