What Is the Direction of the Ball's Projection?

[grando69]

Homework Statement

A child throws a ball with a speed 20ms-1 from a window 5m above horizontal ground. If the ball hits the ground 1.5 seconds later, find the direction of the projection.

Homework Equations

The basic equations of motion:
s=ut+1/2at^2
v=u+at
v^2=u^2+2as

The Attempt at a Solution

 

[hage567]

What have you tried? Show your thoughts.

 

[unique_pavadrin]

try breaking the speed of the ball into component form, so that you have a horizontal and a vertical component. assuming that there is no air resistance, the horizontal component will remain constant as there is no acceleration occurring in the horizontal plane. The only acceleration present is gravity which acts downwards in the vertical plane.
the horizontal component will be: $$ut\cos \theta$$
the vertical component will be: $$ut\sin \theta - \frac{{gt^2 }}{2}$$