The radius of gyration of a body about an axis at a distance of 6 cm from the centre of mass is 10 cm. What is its radius of gyration about a parallel axis through its centre of mass?

Options

A. K = 4 cm
B. K = 6 cm
C. K =10 cm
D. K = 8 cm

Answer

D

Explanation

According to parallel axes theorem,
`I_(o)=I_(c)+Mh^(2)`
`therefore MK'^(2)+MK^(2)+Mh^(2)`
`therefore K'^(2)=K^(2)+h^(2)" "therefore 10^(2)=K^(2)+6^(2)`
`therefore K^(2)=10^(2)-6^(2)=64" "therefore" "K=8cm`