Question 189108: In a pool at a water park, a dolphin jumps out of the water traveling at 20 feet per second. Its height "h", in feet, above the water after "t" seconds is given by the formula h=20t-16t^2. How long is the dolphin in the air before returning to the water? Help. and Thank you.
Answer by ankor@dixie-net.com(22740)   (Show Source):
You can put this solution on YOUR website! a dolphin jumps out of the water traveling at 20 feet per second.
Its height "h", in feet, above the water after "t" seconds is given by the formula h=20t-16t^2.
How long is the dolphin in the air before returning to the water?
:
When the dolphin returns to the water, h = 0, therefore a quadratic equation:
-16t^2 + 20t = 0
Factor our -4t
-4t(4t - 5) = 0
Two solutions:
t = 0 (when the dolphin leaves the water
and
4t = 5
t = 5/4
t = 1.25 seconds when the dolphin returns to the water
:
In the air 1.25 seconds
:
You can check this solution (t=1.25) in the original equation
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