what is the initial velocity of the balla ball is

Question

What is the initial velocity of the ball:

A ball is horizontally thrown from the top of a building 60 m height, hits the horizontal ground 25 m from the base of the building a. What is the initial velocity of the ball?

Solution

Let the top of the building corner be the origin. So

v_x  = v           and                             v _y  = 0

We have

 - 60 = - (½) g t ²

∴ t = 3.5 seconds

x = v t

v = x/t = 25 = 7.143 m / sec.