Question

Benjamin threw a rock straight up from a cliff that was 36 ft above the water. if the height of the rock​ h, in​ feet, after t seconds is given by the equation nbsp h equals negative 16 t squared plus 36 t plus 36​, how long will it take for the rock to hit the​ water?

Answer 1

For this case we have the following equation:
 h (t) = -16t ^ 2 + 36t + 36
 By the time the rock hits the water we have:
 -16t ^ 2 + 36t + 36 = 0
 Solving the second degree polynomial we have:
 t1 = -3/4
 t2 = 3
 We discard the negative root because we want to find the time.
 Answer:
 It will take for the rock to hit the water about:
 t = 3 seconds