Please show step by step work

FOCUS PROBLEMS: 1) The velocity of a car traveling in a straight line, in feet per second, is shown in the table below. Time, t (sec) 0 10 15 20 25 30 35 40 45 50 Velocity, v (ft./sec.) 0 12 20. 30 55 70 78 81 75 60 72 a) On a sheet of graph paper sketch a careful graph of this data and draw a smooth curve through the data. b) During what intervals of time is the acceleration of the car positive? c) Find the average acceleration of the car over the interval 0 s t $ 50. d) Approximate the acceleration of the car at 1 - 40 seconds. Explain your calculation. e) What is the greatest distance the car could have traveled during the period from ? = 0 to t = 50 seconds? Comment on any assumptions you are making. (Hint: be careful to overestimate on each interval by choosing either the left or right endpoints, as appropriate.)