JEE Main 2014 · 9 Apr · Shift 1, Physics question 2

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