SOLUTION: Benjamin threw a rock straight up from a cliff that was 100 ft above the water. If the height of the rock h, in feet, after t seconds is given by the equation h = -16t^2+60t+100, h

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Question 898239: Benjamin threw a rock straight up from a cliff that was 100 ft above the water. If the height of the rock h, in feet, after t seconds is given by the equation h = -16t^2+60t+100, how long will it take for the rock to hit the water?
Answer by lwsshak3(11628) About Me  (Show Source):
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Benjamin threw a rock straight up from a cliff that was 100 ft above the water. If the height of the rock h, in feet, after t seconds is given by the equation h = -16t^2+60t+100, how long will it take for the rock to hit the water?
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h= -16t^2+60t+100
0=(t-5)(-16t-20)
t=5
how long will it take for the rock to hit the water? 5 sec