Question

A rock is thrown straight up at a velocity of +30. m/s from a height of 2 m above the ground. How high does it go? How long will it take to fall back to the same height from which it was thrown?

Answer 1

h(t) = 2 + 20t - 4.9t^2
as with all parabolas, the vertex is at t = -b/2a = 20/9.8
time down = time up