Question

1.
The principal axes of a cross-section are defined
(a) the axes about which radius of gyration is
zero
(b) the axes about which product of inertia is
Zero
(c) the axes about which polar moment of
inertia is zero
(d) the axes about which modulus of section is​

Answer 1

Answer:

b) the axes about which product of inertia is

Zero

Answer 2

Answer:

   The principal axes of a cross-section are defined as the axes about which product of inertia is zero (option b).

Explanation:

• The principal axes of any rigid body are those for which the products of inertia are all zero resulting in an inertia matrix of the form.
• The principal axes are the main axes of a member which are perpendicular and intersect each other at the center of the area or “centroid”.