Question

The radius of gyration of a body about an axis at a distance of $6cm$ from its centre of mass is $10cm$. Then its radius of gyration about a parallel axis through its centre of mass will be:

• A. $80cm$
• B. $8cm$
• C. $0.8cm$
• D. $80m$

Answer 1

Answer: (B)

$8cm$

radius of gyration
$K_{00}=10cm$
$I_{00}=I_{AM}+6^{2}M$ (governing equation formed as per given conditions in question)
${10}^{2}M=I_{AA}+36M$
$100M-36M=I_{AA}$
$64M=I_{AA}$
for radius of gyration about axis passing through COM.
$M{K}^2=64M$
$\therefore K=8cm$