3. The position, from a fixed point of an object moving along a straight line is given by s(t) = # t2 + 24 t + 6, where s(t) is the object's position, in metres, after t seconds. [6 marks] a) Find the object's velocity at 3 seconds. b) Find the object's acceleration at 2.4 seconds. c) Determine when the object is stationary