Problema Solution

Benjamin threw a rock straight up from a cliff that was 96 ft above the water. If the height of the rock h, in feet, after t second is given by the equation h=-16t^2+116t+96, how long will it take for the rock to hit the water?

Answer provided by our tutors

h=-16t^2+116t+96


the rock will hit the water for some t, t>0 when h(t) = 0 that is


-16t^2+116t+96 = 0


by solving we find:


t = 8 s


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it takes 8 seconds for the rock to hit the water.