You can put this solution on YOUR website!
Pole vaulting. In 1981 Vladimir Poliakov (USSR)
set a world record of 19 ft 3/4
in. for the pole vault
(www.polevault.com). To reach that height, Poliakov
obtained a speed of approximately 36 feet per second on
the runway. The formula h _ _16t2 _ 36t gives his
height t seconds after leaving the ground.
h = -16t^2 + 36t
a) Use the formula to find the exact values of t for which
his height was 18 feet.
18 = -16t^2 + 36t
8t^2 - 18t + 9 = 0
t = 0.75 seconds (going up)
t = 1.5 seconds (coming down)
t found using quadratic equation. If you have questions, email me via the thank you note.
b) Use the accompanying graph to estimate the value of t
for which he was at his maximum height.
I don't see a graph, but the easiest way to find max height is to get the average of the 2 values of t above.
t = 1.125 seconds
c) Approximately how long was he in the air?
That would be 2 times the time at max height, or 2.25 seconds.