A ball is thrown horizontally from the top of a building 21.6 m high. The ball strikes the ground at a point 123 m from the base of the building. Find the x component of its velocity just before it strikes the ground. Find the y component of its velocity just before it strikes the ground.

h = Vo*t + 0.5g*t^2 = 21.6 m.

0 + 4.9t^2 = 21.6,
t^2 = 4.41,
Tf=2.10 s. = Fall time.=Time in flight.

Yf^2 = Vo^2 + 2g*d,
Yf^2 = 0 + 19.6*21.6 m.
Yf^2 = 423.4,
Yf = 20.6 m/s. = Final velocity.

Dx = Xo*Tf = 123,
Xo*2.10 = 123,
Xo = 123 / 2.1 = 58.6 m/s.