A person throws a ball horizontally from the top of a building that is 24.0 m above the ground level. The ball lands 100 m down range from the base of the building. What was the initial velocity of the ball? What is the speed of the ball when reaches the ground?

a) Initial velocity = 0 m/s

b) Final velocity at ground = 21.7 m/s

Explanation:

We consider only vertical motion for the required information.

The ball travels a vertical distance equal to the height of the building.  See the attached file diagram.

At point A the initial velocity of the ball will be zero because it just starts from there. So

Initial velocity =Vi= 0 m/s

During its flight the ball travels a vertical distance equal to the height od the building.

Distance =S=24m

Gravitational acceleration = g= 9.8 m/sec2

Velocity at point B = Vf=?

Using

××=

==>

==> Vf =

==> Vf= 21.7 m/sec

So the ball will hit the ground with 21.7 m/s velocity

second mirror gathers light from a faraway object and reflects it to another mirror. - a.

hi there!

out of the two, (b) precision would be more reasonable.   however, both a and b could be pretty reasonable.

-awesomerepublic   : )