Answer:
h(t) = -16t^2 + 40t + 120
h(t) = -16(t^2 - 5/2*t) + 120
h(t) = -16(t^2 - 5/2*t + (5/4)^2 - (5/4)^2) + 120
h(t) = -16(t^2 - 5/2*t + (5/4)^2 - 25/16) + 120
h(t) = -16(t^2 - 5/2*t + (5/4)^2) + 120 + 25
h(t) = -16(t - 5/4)^2 + 145
The rock needs 5/4 = 1.25 seconds to travel to the highest point wich is 145 m high.
