The tensor analog of this quantity can be diagonalized by defining a coordinate system along the principal axes, and its middle eigenvalue corresponds to unstable motion according to Euler's Equations of Motion.  The deflecti
The tensor analog of this quantity can be diagonalized by defining a coordinate system along the principal axes, and its middle eigenvalue corresponds to unstable motion according to Euler's Equations of Motion.  The deflection of a cantilevered beam is inversely proportional to Young's modulus and this quantity.  It is given by "cross-sectional area times the square of the radius of gyration", and it can be found by the parallel axis theorem.  For a sphere it is equal to "two-fifths m r squared", while it has half the value for a disc that it has for a ring.  For 10 points, name this quantity symbolized "I", the rotational analog of mass.
The tensor analog of this quantity can be diagonalized by defining a coordinate system along the principal axes, and its middle eigenvalue corresponds to unstable motion according to Euler's Equations of Motion.  
mass moment of inertia [prompt on angular mass]