Describe moment of inertia and torque for a rotating rigid body. Find the expression for rotational kinetic energy and discuss the conditions for conservation.

--- The inability of a body to change its state of rest or uniform rotational motion by itself is called inertia. For a rotating body, this property is called the Moment of Inertia. For a system of particles with masses m₁, m₂, m₃, ..., mₙ at perpendicular distances r₁, r₂, r₃, ..., rₙ from the a...