(a) The power (in watts) from an engine is represented by the equation: P = 100t14 +6t , where t is the time in seconds. Draw the graph that represents power against time for this engine for time t=0 to 20 seconds. Show the area on the graph which represents the energy converted between 5 s and 15 s. Show, using summation, how you would gain an approximation for the energy. Using integration, evaluate the exact energy between 5 s and 15 s. (b) Part of a machine moves with a velocity given by the expression: v =7t' + 0.8t mm/s. Calculate the displacement over the first 5 seconds of motion