Physics

Problem

Mass per unit area of a circular disc of radius

a

depends on the distance

r

from its centre as

\sigma(r) = A + Br

. The moment of inertia of the disc about the axis, perpendicular to the plane and passing through its centre is: a.

2\pi a^4 \left( \frac{A}{4} + \frac{aB}{5} \right)

2\pi a^4 \left( \frac{aA}{4} + \frac{B}{5} \right)

\pi a^4 \left( \frac{A}{4} + \frac{aB}{5} \right)

2\pi a^4 \left( \frac{A}{4} + \frac{B}{5} \right)