Question 627: Centre of Mass and Rotational Motion

Question

The ratio of the radius of gyration of a thin uniform disc about an axis passing through its centre and normal to its plane to the radius of gyration of the disc about its diameter is

Accepted Answer

$${l_1} = {{M{R^2}} \over 2}$$
$${k_1} = \sqrt {{{{l_1}} \over M}} $$
$$ = {R \over {\sqrt 2 }}$$
$${l_2} = {{M{R^2}} \over 4}$$
$${k_2} = \sqrt {{{{l_2}} \over M}} $$
$$ = {R \over 2}$$
$${{{k_1}} \over {{k_2}}} = {{{R \over {\sqrt 2 }}} \over {{R \over 2}}}$$
$$ = \sqrt 2 :1$$

Answer

2 : 1

Answer

$$\sqrt2$$ : 1

Answer

4 : 1

Answer

1 : $$\sqrt2$$

Centre of Mass and Rotational Motion

The ratio of the radius of gyration of a thin uniform disc about an axis passing through its centre and normal to its plane to the radius of gyration of the disc about its diameter is

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