Vamos calcular a velocidade vertical inicial do projétil:
[tex]V^2=V_0^2+2a\Delta S\Longrightarrow V_y^2=V_0_y^2+2g\Delta S\Longrightarrow0^2=V_0_y^2+2(-10)\cdot200\\\\\Longrightarrow
0=V_0_y^2-4000\Longrightarrow V_0_y^2=4000\Longrightarrow V_0_y=20\sqrt{10}\;m/s\\\\\\
V_0_y=V_0\cdot\sin45^{\circ}\Longrightarrow20\sqrt{10}=V_0\cdot\dfrac{\sqrt{2}}{2}\Longrightarrow V_0=\dfrac{20\sqrt{10}}{\frac{\sqrt{2}}{2}}\Longrightarrow \boxed{V_0=40\sqrt{5}\;m/s}[/tex]
