JEE Main · 2026 · 28 Jan 2026 · Shift 2 · Vector

Under the inversion $\vec{r}\to -\vec{r}$, every polar (true) vector reverses: velocity $\vec{v}=\frac{d\vec{r}}{dt}\to -\vec{v}$, momentum $\vec{p}=m\vec{v}\to -\vec{p}$, and acceleration $\vec{a}=\frac{d\vec{v}}{dt}\to -\vec{a}$. Angular momentum, however, is the cross product $\vec{L}=\vec{r}\times \vec{p}$; with both factors reversing, $\vec{L}\to (-\vec{r})\times (-\vec{p})=\vec{r}\times \vec{p}=\vec{L}$. Being an axial (pseudo) vector, angular momentum does not flip under the sign change.