your ordered pairs are of the form (x,y) = (distance,height)
so, as the problem stated, x is the horizontal distance and y is the height
the formula you used, -b/(2a) , would give you the distance at which the max height occurs.
so if x = 91.125 ft, you have to sub that into your original equation to find y, the max height
Secondly , the 91.125 is the distance it went to reach the maximum height, so of course it
also has to come back down. What would be that distance?
look at the first graph of
https://www.wolframalpha.com/input/?i=plot+y%3D%28-20%2F2025%29x%5E2+%2B%289%2F5%29x+%2B1.6
The height y in feet of a punted football is given by y=(-20/2025)x^2 +(9/5)x +1.6 where x is the horizontal distance in feet from the point at which the ball is punted.
a) How high is the ball when it is punted?
my answer:
x=0 because it is at the ground and the ball is punted from the ground which is 0
y=(-20/2025)x^2 +(9/5)x +1.6
y=(-20/2025)(0)^2 +(9/5)(0) +1.6
y = 0 +0 +1.6
y = 1.6
the football is 1.6 ft above the ground
b) what is the maximum height of the punt? how long is the punt?
my answer:
-b/2a
=(-9/5)/2(-20/2025)
=(-9/5)/(-8/405)
=91.125
the max height is 91.125 ft
I need on on question b) how long is the punt and is my answers correct?
1 answer
1 answer