SOLUTION: A flag is raised while an onlooker watches from a distance of 21 feet away from the base of the flag pole (see the figure below). The flag rises vertically at a rate of 8 inches pe

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons -> SOLUTION: A flag is raised while an onlooker watches from a distance of 21 feet away from the base of the flag pole (see the figure below). The flag rises vertically at a rate of 8 inches pe      Log On


   

Question 567353: A flag is raised while an onlooker watches from a distance of 21 feet away from the base of the flag pole (see the figure below). The flag rises vertically at a rate of 8 inches per second. Let t denote the time (in seconds) after the flag begins to rise (For simplicity, assume that when the flag begins to rise it is 0 inches above the ground). Express the distance d (in feet) between the flag and the onlooker as a function of t.
All of the answers I come up with are incorrect! Any help is greatly appreciated!!! Thanks!
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
A flag is raised while an onlooker watches from a distance of 21 feet away from the base of the flag pole (see the figure below).
The flag rises vertically at a rate of 8 inches per second.
Let t denote the time (in seconds) after the flag begins to rise (For simplicity, assume that when the flag begins to rise it is 0 inches above the ground).
Express the distance d (in feet) between the flag and the onlooker as a function of t.
:
They want this in feet; convert 8" to 2%2F3ft
:
The distance from the onlooker to the flag is the hypotenuse, formed by the 21' from the base of the pole and height of the flag which would be 2%2F3t
:
d(t) = sqrt%2821%5E2+%2B+%28%282%2F3%29t%29%5E2%29
d(t) = sqrt%28441+%2B+%284%2F9%29t%5E2%29