Saturday, August 16, 2014

The first moment of area equals the summation of area times distance to an axis [Σ(a x r)]. It is a measure of the distribution of the area of a shape in relationship to an axis. 
First moment of area is commonly used in engineering applications to determine the centroid of an object or the statical moment of area. 


b) The second moment of area, also known as the area moment of inertia or second moment of inertia, is a property of a shape that is used to predict its resistance to bending and deflection which are directly proportional.

second moment of area= Ar^2 

c) Mass moment of inertia or the angular mass, is the rotational analog of mass. That is, it is the inertia of a rigid rotating body with respect to its rotation. 

Here, its again the very old discussion. The above part is second moment of area. Here, its of mass. 

Mass Moment of inetia = mr^2
-PROFESSOR  PRADEEP KARNA