If ball remains in air for total time T = 0.85 s
this is also known as time of flight
In order to find the time of flight we can use kinematics
[tex]\Delta Y = v_y*t + \frac{1}{2}at^2[/tex]
so for complete motion its displacement in y direction will be zero
[tex]0 = v_y* 0.85 + \frac{1}{2}(-9.8)(0.85^2)[/tex]
[tex]0 = v_y*0.85 - 3.54[/tex]
[tex]v_y = 4.165 m/s[/tex]
now we know that net velocity of the ball is 8 m/s
while is y direction component we got is vy = 4.165 m/s
now by component method we can say
[tex]v_y = v sin\theta[/tex]
[tex]4.165 = 8 sin\theta[/tex]
[tex]\theta = sin^{-1}\frac{4.165}{8}[/tex]
[tex]\theta = 31.4^0 [/tex]
so it is projected at an angle of 31.4 degree above horizontal
