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Determining Average Rate of Change If a ball is thrown straight upward with an initial velocity of 80 feet per second, its height above the ground, in feet, can be written as h(t) = -16t + 80t, where t denotes the time in seconds that the ball has been airborne. What was the average rate of change of the height of the ball over the first 2 seconds? f(b) - f(a) Hint: The average rate of change of a function f(a) over the interval [a, b] is found by evaluating b - a The answer is feet per second. ( Enter your answer as a numerical value. If the answer is a fraction it must be simplified. )