posted by Anonymous .
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.
Compute how long it takes to fall 21.6 m. Call that time T. You should know that formula.
If not, derive it from
H = 123 m = (g/2) T^2.
The vertical velocity when it hits ground is g*T.
The horizontal velocity remains 123 m/T during flight.