# How to calculate the moment of inertia of a 2 point mass system

I have 2 point masses $m_1$ and $m_2$ connected via a massless rigid rod to a center. $m_1$ is at the distance $r_1$ from the center and $m_2$ is at the distance $r_2$ from the center. How would i calculate the moment of inertia of the system?

• Are you looking for the MMOI about the rod center, or the center of mass? The former is going to be larger than the latter. – ja72 Jan 15 '16 at 5:32

$$I=\sum_i m_ir_i^2 =m_1r_1^2+m_2r_2^2+...$$