SOLUTION: The function y= -16t^2+486 models the height in feet of a stone t seconds after it is dropped from the edge of a vertical cliff. How long will it take the stone to hit the ground?

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Question 764674: The function y= -16t^2+486 models the height in feet of a stone t seconds after it is dropped from the edge of a vertical cliff. How long will it take the stone to hit the ground? Round to the nearest hundredth of a second.
Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
y= -16t^2+486
set y to zero and solve for t:
0 = -16t^2+486
0 = 16t^2-486
486 = 16t^2
486/16 = t^2
30.375 = t^2
5.51 seconds = t