A ball is thrown from a 20.0m high building and hits the ground 6.0m from the building. With what horizontal velocity was it thrown?
h = ho - (Vo*t + 0.5g*t^2) = 0.
20 - (0 + 4.9t^2) = 0
20 - 4.9t^2 = 0
-4.9t^2 = -20
t^2 = 4.08
Tf = 2.02 s. = Fall time.
Range = Xo * Tf = 6 m.
Xo*2.02 = 6
Xo = 2.97 m/s. = Initial hor. velocity.