JIPMER Jipmer Medical Solved Paper-2002

  • question_answer
    Two solid spheres of iron have radii in the ratio 1 : 2, their moments of inertia will be in the ratio:

    A)  1 : 32                    

    B)  1 : 16                    

    C)  1 : 8                      

    D)         1 : 4

    Correct Answer: A

    Solution :

                    From the formula the moment of inertia of sphere is \[I=\frac{2}{5}m{{r}^{2}}\]           where \[m=\frac{4}{3}\pi {{r}^{3}}\rho \] where \[\rho \] is the density of the body so,          \[I=\frac{2{{r}^{2}}}{5}\times \frac{4}{3}\pi {{r}^{3}}\rho =\frac{8}{15}\pi \rho {{r}^{3}}\] \[I\propto {{r}^{5}}\] Therefore, moment of inertia is proportional to\[{{r}^{5}}\]. Hence ratio will be\[1:{{2}^{5}}=1:32.\]


You need to login to perform this action.
You will be redirected in 3 sec spinner