An canon ball is launched from ground level directly upward at 39.2 m/s. For how long is the canon ball at or above a height of 34.3 meters?

Answer 1

h = Yo*t + 0.5g*t^2 = 34.3
39.2t - 4.9t^2 = 34.3
-4.9t^2 + 39.2t - 34.3 = 0
t = 1 s. (Used Quad. Formula).