
Concept explainers
a.
To graph:The path of th football.
a.

Explanation of Solution
Given:
The equation of the path of football is y=−162025x2+95x+32
Formula/ concept used:
The graph is drawn using graphing calculator.
Graph:
The graph for function (trajectory) is shown in Figure-1 here.
Interpretation of Graph:
The graph of path of football is a parabola with vertex (113.906,104.016) .
b.
The height of the football when it is punted.
b.

Answer to Problem 65E
The height of football when it is punted is 1.5 feet.
Explanation of Solution
Given:
The equation of path of football is y=−162025x2+95x+32 .
Concept used:
The initial height when football is punted is obtained when x=0 .
Calculations:
The equation of path of football is y(x)=−162025x2+95x+32 where x and y (in feet) are the horizontal and vertical position of the football respectively.
Therefore, the initial vertical position or the height of football when it is punted is y(0)=−162025(0)2+95(0)+32=1.5 feet.
Conclusion:
The height of football when it is punted is 1.5 feet.
c.
The maximum height of the football.
c.

Answer to Problem 65E
The maximum height of the football is 104.016 feet.
Explanation of Solution
Given:
The equation of path of football in part (a)
Conceptused:
When the parabola opens downward its
Calculations:
From the graph in part (a), the vertex of the parabola represented by the equation of the path of football y(x)=−162025x2+95x+32 is (113.906,104.016)=(h,ymax.) .
Thus, ymax.=104.016 .
The maximum height of the football is 104.016 feet.
Conclusion:
The maximum height of the football is 104.016 feet.
d.
The horizontal distance the football strike the ground
d.

Answer to Problem 65E
The football strikes the ground at horizontal distance x=228.643 feet from the initial point.
Explanation of Solution
Given:
The equation of path of football in part (a).
Formula used:
The football strikes the ground when its vertical height is zero.
Calculations:
The equation of path of footballis y(x)=−162025x2+95x+32 .
The football will on the ground when y(x)=0 .
From the graph in part (a) we see that y(x)=0 when x=228.643
Thus,the football strikes the ground at horizontal distance x=228.643 feet from the initial point.
Conclusion:
The football strikes the ground at horizontal distance x=228.643 feet from the initial point.
e.
To compare: The results from parts (b), (c), and (d).
e.

Answer to Problem 65E
The results obtained parts (b), (c), and (d) are identical.
Explanation of Solution
Given:
The results obtained in parts (b), (c), and (d).
Explanations:
In parts (b), (c), and (d) we find that the area Amax.=2500 sq. ft. when x=25 and y=50 ft.
Thus, the results obtained parts (b), (c), and (d) are identical.
Chapter 2 Solutions
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