Question

Difference between longitudinal and polar axis in strength of material

Answer 1

Longitudinal axis in simple language is the axis along the length. Technically it is if you divide your whole object in small parts(strips) along its length and if you join the centroid of each part , the axis obtained is longitudinal

Polar modulus is defined as the ratio of the polar moment of inertia to the radius of the shaft. It is also called as torsional section modulus. It is denoted by Zp.