Question
A person jumps off a 20m high cliff into water below. The height of the person above the ground at time t seconds is given by the equation h=-5t^2+30. How long does it take the person to reach the half way mark to the water?
Answers
Steve
10 = -5t^2 + 30
5t^2 = 20
t^2 = 4
t = 2
5t^2 = 20
t^2 = 4
t = 2