Question

(D) depends on the time
Two spheres of same mass and radius are in
contact with each other. If the moment om
inertia of a sphere about its diameter is,
then the moment of inertia of both the spheres
about the tangent at their common point
would be -
(A) 31
(B) 71
(C) 41
(D)/51​

Answer 1

Solution:

Moment of inertia of a sphere about its diameter:

$\bullet$ $\boxed{\sf{I=\frac{2}{5}\:MR^{2}}}$

Moment of inertia of the sphere about the tangent:

From parallel axes theorem,

I' = 2/5 MR^2 + MR^2

I' = 7/5 MR^2

Total moment of inertia of both spheres about the common tangent:

$\sf{I_{total}}$ = 2I'

$\implies$ 2 × 7/5 MR^2

$\implies$ 14/5 MR^2

$\implies$ 14/5 MR^2 × I / 2/5 MR^2

$\implies$ 7I

Therefore:

Correct option: (B) 7I

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Answered by: Niki Swar, Goa❤️