The radius of gyration of a disc of mass 100 g and radius 5 cm about an axis pasing through centre of gravity and perpendicular to the plane is

Options

A. 3.54 cm
B. 1.54 cm
C. 4.54 cm
D. 2.54 cm

Answer

A

Explanation

Moment of inertia of circular disc is given by
`l=(1)/(2)mR^(2)`
`therefore" "(1)/(2)mR^(2)=mL^(2)`
`rArr" "K^(2)=(R^(2))/(2)`
`"or "K=(R)/(sqrt2)=(5)/(sqrt2)=3.54 cm`