Question in dynamics projectile motion

[abdo99]

Attempt solution

Y=(vsinø)t-0.5gt^2
4=(vsinø)t-4,9t^2

But there is 3 variables!

Another eq is
X=(vcosø)t
6=(vcosø)t

But i did not found any away to solution

 

[dauto]

You posted a sideways picture

 

[rtsswmdktbmhw]

Hint: 1. The ball travels on a parabolic path.

2. If you know the max height of the ball, you can calculate the vertical and horizontal components of initial velocity.

Or, at least, that's how I managed to do it but there may be a simpler method/formula..

 

[abdo99]

I know that ,but i did not konw the maximum H
The rule is H=(u^2sin^2)/2g