I The graph of the velocity 1:0?) , in ftfsec, of a car traveling on a straight road, for 0 S t S 35, is shown in the gure. (a) Find the average acceleration of the car, in ,1\" sec2 , over the interval 0 E t E 35. (b) Find an approximation for the acceleration of the car, in it I sec2 , at t = 20. Show your computations. 35 (c) Approximate I5 12(3) 0'!\" with a Riemann sum, using the midpoints of three subintervals of equal length. Explain the meaning of this integral