A ball is thrown upwards off the edge of a balcony. As it comes back down it misses the balcony and falls until it hits the ground below. The height, s(t) of the ball in feet after t seconds is given by s(t) = 16t 2 + 25t + 20. (a) Find the slope of the secant line between t = 1 and t = 1.5 seconds (b) Interpret your answer as an average rate of change. That is, what does the slope of the secant line tell you about how the height of the ball is changing? (c) What are the units of the slope of the secant line?