Assertion : Centre of mass of a system may or may not lie inside...

- Assertion (A): True. The centre of mass (COM) can lie inside or outside the material of the body/system. Examples: for a uniform ring or a semicircular wire, the COM lies at the geometric center-which is empty space. - Reason (R): True. The COM position is determined by the mass distribution: (\vec{R}_{C M}=\frac{\sum m_i \vec{r} i}{\sum m_i} \quad \text{ or } \quad \vec{R} C M=\frac{1}{M} \int \vec{r} d m) Change how mass is spread, and the COM shifts accordingly. - Does R explain A? Yes. Because COM depends on how mass is distributed, certain distributions (like mass arranged around a hole) naturally place the COM in a region with no material, explaining why COM may be outside the system. Hence, both A and R are true, and R correctly explains A (\rightarrow) Option (1).