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

Question

$(a)\;tan^{-1} \large\frac{2}{3} \qquad(b)\;tan^{-1} \large\frac{3}{2} \qquad(c)\;tan^{-1} \large\frac{7}{4} \qquad(d)\;tan^{-1} \large\frac{4}{5}$