I was studying rotational mechanics a while ago, and came across the idea of moment of inertia. The moment of inertia of an object describes its resistance to angular acceleration. The definition of the moment of inertia of a point mass about a fixed point is $mr^2$. I understand why the mass of the object dampens the angular acceleration caused by a torque. However, why is the moment of inertia proportional to the square of its distance from the fixed point?
I just want some motivation as to why it was defined this way.
