Question

Explain the principle of the polar second moment of area, J, and why its units are m⁴.

Answer 1

Polar Moment of inertia is taken moment of area with distance r² so we see the area is multiply by the r² so its unit is fourth power of m⁴ .Polar moment of inertia principle finding moment of inertia about an axes O-O of the area it give polar moment of inertia.it basicallly give resistance in Torsional case as moment of inertia in Rotation.Inertia in translation.