Question

Two discs of same mass and same thickness have densities as 17 g/cm351g/cm 3. The ratio of their moment of inertia about their central axes is?????

Answer 1

we know,
momentum of inertia of disc about its centre is given by $I=\frac{1}{2}Mr^2$
where r the radius of disc.

volume of disc = base area × thickness
V = πr² × L
so, mass of disc = density × volume
m = d × V = dπr²L
r² = M/dπL
so, I = M(M/dπL) = M²/dπL
so, here π, L are constant .
therefore, moment of inertia is inversely proportional to density of disc.

so, if mass and thickness of disc are same
then, ratio of their moment of inertia should be
$\frac{I_1}{I_2}=\frac{d_2}{d_1}$

= $\frac{351}{17}$

Answer 2

Answer:

above given answer is correct

Explanation:

same can be asked with different values as 17g/cm3,51 g cm3....so here also same 51/17

so,it's a readymade Question.....by heart the way..

cheer up ..

good day...

all the best mate