A football player throws a 27-meters pass horizontally from an initial height of 1.8 m above the level ground below. How fast was the ball thrown? Show all work.

45 m/s

Explanation:

In throwing instant, ball has HORIZONTAL SPEED (V) and  VERTICAL SPEED (0). Horizontal speed remains stable but VERTICAL SPEED increases from 0 to last vertical speed.  

First, we should know the time. How much time the ball will travel.

For this, we should think free fall.

h=(1/2).a.

1.8=5.

t=0.6 s

During this period, ball will move free fall  BUT at the same time, travel horizontally with constant horizontal speed.

V=x/t =27/0.6 = 45 m/s

In throwing instant, ball has HORIZONTAL SPEED (45m/s) and  VERTICAL SPEED (0). Horizontal speed remains stable but VERTICAL SPEED increases from 0 to last vertical speed.