Question 724225: A diver is standing on a platform 24 feet above the pool. He jumps from the platform with an initial upward velocity of 8ft/s. How long will it take for him to hit the water? I know the formula is h=-16t^2+vt+s, but I don't understand the difference between h and s.
Answer by ankor@dixie-net.com(22740)   (Show Source):
You can put this solution on YOUR website! A diver is standing on a platform 24 feet above the pool.
He jumps from the platform with an initial upward velocity of 8ft/s.
How long will it take for him to hit the water?
I know the formula is h=-16t^2+vt+s, but I don't understand the difference between h and s.
:
The Formula h = -16t^2 + vt + s; where
h = height after t seconds
t = time in seconds
v = upward velocity
s = initial height (t=0)
also note that
-16t^2 represents the downward force of gravity for t seconds
+vt = the upward force for t seconds
:
the height when he hits the water = 0 therefore:
0 = -16t^2 + 8t + 24
usually written
-16t^2 + 8t + 24 = 0
we can simplify this, divide by -8, then we have
2t^2 - t - 3 = 0
this will factor to
(2t - 3)(t + 1) = 0
the positive solution
2t = 3
t = 3/2
t = 1.5 seconds to hit the water
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