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Question

Answer 1

h(t) = 0 = -16t^2 + 40

t^2 = 40/16 = 10/4 = 5/2 = 2 1/2 seconds to reach the water

graph it, it's a downward opening parabola with y intercept = 40, vertex (0,40) = maximum point

x intercepts = 2.5 and - 2.5, axis of symmetry is x=0