A graphing calculator may NOT be used for the following problem. t (minutes) 0 3 6 10 12 20 U(t) (meters per minute) 100 110 150 220 175 John is riding a bike ride along a straight path. For 0 s t's 20, John's velocity is given by a differentiable function, v. Selected values of v(t), where t is measured in minutes and u(t) is measured in meters per minute, are given in the table above a) Using correct units, estimate John's average acceleration at t = 8 minutes. b) Sam is jogging along the same path. For 0 s t s 5, Sam's velocity is modeled by v(t) = 0.5t3 - 2t2 + 100. Find her acceleration at time t = 3. c) At time t = 3, John is at a position x, = 200 meters and Sam is at a position x, = 300 meters, as measured from Sam's starting point. Find the rate, in meters per minute, at which the distance between John and Sam is changing at time t = 3. d) At time t = 2, is Sam speeding up or slowing down