JEE Main 2022 · 28 Jun · Shift 1, Physics question 55

The position vector of 1 kg object is $\vec r=\left(3\hat i-\hat j\right)$ m and its velocity $\vec v=\left(3\hat j+\hat k\right)$ ms$^{-1}$. The magnitude of its angular momentum is $\sqrt x$ Nm where $x$ is ______.