Question

Define area moment of inertia and product of inertia

Answer 1

The product of inertia of area A relative to the indicated XY rectangular axes is IXY = ∫ xy dA . The product of inertia of the mass contained in volume V relative to the XY axes is IXY = ∫ xyρ dV—similarly for IYZ and IZX. Relative to principal axes of inertia, the product of inertia of a figure is zero

Answer 2

Ciao,
momment of inertia is the product of mass and square of radius.
I= mr2.
it is the quantity that determines the torque in a rotating body.
hope it helps you