question_answer

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

A)  800cm                                 

B)  8cm                      

C)  0.8cm                  

D)         80m         

Correct Answer: B

Solution :

\[\cos \phi =\frac{R}{\sqrt{{{R}^{2}}+{{\omega }^{2}}{{L}^{2}}}}\] \[\approx \frac{R}{\omega L}\] \[R<<\omega L\] Given, \[R<<\omega L\], Putting them, we get \[\cos \phi \]