If a ball is thrown vertically upward from the roof of 48 foot building with a velocity of 80 ft/sec, its height after t seconds is s(t) = 48+80t-16t^2

Question

What is the velocity of the ball when it hits the ground?

Answer 1

When the ball returns to the roof, its
velocity will be 80 Ft/s.

V^2 = Vo^2 + 2g*h = 80^2 + 64*48 = 9472
V = 97.32 Ft/s.