Question 310286: A rock falls from the top of a cliff into a river 96 feet below. The equation h=-16t^2+s, s is the starting height, after a given number of seconds, t, and h is the height. How long would it take the rock to hit the water. can someone explain this to me in another way because I don't get it. Thanks
Answer by ankor@dixie-net.com(22740)   (Show Source):
You can put this solution on YOUR website! A rock falls from the top of a cliff into a river 96 feet below.
The equation h=-16t^2+s, s is the starting height, after a given number of
seconds, t, and h is the height.
How long would it take the rock to hit the water.
:
Understand that gravity (on earth) accelerates an object downward 16 ft/sec every second, hence:
-16t^2 and given s as the height of the object initially; 96 ft, (t=0)
when it strikes the ground h = 0, right?
so we have
-16t^2 + 96 = 0
Simplify, divide both sides by -16, this also changes the signs and you have
(t^2 - 6) = 0
t^2 = +6
t = 
t = 2.45 secs to hit the ground
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