The position of a projectile launched from the origin at t =0 is given by r =(40 i +50 j ) m at t =2 s. If the projectile was launched at an angle θ…

The position of a projectile launched from the origin at $\displaystyle \mathrm{t}=0$ is given by $\displaystyle \overrightarrow{\mathrm{r}}=(40 \hat{i}+50 \hat{j}) \mathrm{m}$ at $\displaystyle \mathrm{t}=2 \mathrm{~s}$. If the projectile was launched at an angle $\displaystyle \theta$ from the horizontal, then $\displaystyle \theta$ is (take $\displaystyle \mathrm{g}=10 \mathrm{~ms}^{-2}$ ).