Four point masses, each of mass 2.0 $kg$ are placed at the corners of a square of side 1.4 $m$. Find the moment of inertia of this system about an axis that is perpendicular to the plane of the square and passes through one of the masses.
The system is set rotating about the above axis with kinetic energy of 216.0 J. Find the number of revolutions the system makes per minute. Note: You do not need to enter the units, rev/min.