APPLICATION 4. The position function of a moving object is given by s(t) = t3 - 15t2 + 63t + 4, t 2 0, where s is measured in metres at time t, in seconds. [7 marks - 2, 2, 1, 2] (a) Determine the object's velocity at 2 seconds. (b) Determine the object's acceleration at 2 seconds. (c) Is the object speeding up or slowing down at t = 2 seconds? Justify your answer. (d) Determine the times when the object is momentarily at rest. 5. An ice cream company estimates that the cost, C, in dollars of producing x containers of ice cream is C(x) = 0.002x2 + 1.75x + 4100. The demand function, p, in dollars, for selling x containers of ice cream is p(x) = 8.50. (a) Determine the marginal profit from selling 2000 containers of ice cream. [4] (b) Is selling 2000 containers of ice cream a wise business decision for the company? Justify your answer. [1