Answer:
-17 ft/s
Step-by-step explanation:
The average rate of change is the difference in height on the interval, divided by the difference in time.
m = (h(4.5) -h(2))/(4.5 -2) . . . . . . . . definition of rate of change on [2, 4.5]
h(4.5) = (-16·4.5 +87)(4.5) = 67.5
h(2) = (-16·2 +87)(2) = 110
Then ...
m = (67.5 -110)/(2.5) = -17
The average rate of change on the interval from 2 to 4.5 seconds is -17 ft/s.
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Check
The slope of the curve is given by its derivative:
h'(t) = -32t +87
The midpoint of the interval is (2+4.5)/2 = 3.25.
The slope at the midpoint is ...
h'(3.25) = -32(3.25) +87 = -17 . . . . average rate of change on [2, 4.5]
For a quadratic function. the average rate of change on an interval is the slope of the function at the midpoint of the interval. This calculation confirms that.
