9. A stone is thrown from the top of a bridge into a lake below such that its height, h, in metres, can be modeled by the function h(t) = 60-8t - 4.9+2, where + is measured in seconds. Round to one decimal place if necessary. [4 marks] *Be sure to state your interval** a) Determine the average rate of change for the first 2 seconds. b) Estimate the instantaneous rate of change of the height of the shoe at 3 seconds. [A: 3 marks]