1
IIT-JEE 2006
+3
-1

A solid sphere of radius $R$ has moment of inertia $I$ about its geometrical axis. If it is melted into a disc of radius $r$ and thickness $t$. If its moment of inertia about the tangential axis (which is perpendicular to plane of the disc), is also equal to $I$, then the value of $r$ is equal to

A

$\frac{2}{\sqrt{15}} R$

B

$\frac{2}{\sqrt{5}} R$

C

$\frac{3}{\sqrt{15}} R$

D

$\frac{\sqrt{3}}{\sqrt{15}} R$

2
IIT-JEE 2001
+2
-1

One quarter section is cut from a uniform circular disc of radius $R$. This section has a mass $M$. It is made to rotate about a line perpendicular to its plane and passing through the centre of the original disc. Its moment of inertia about the axis of rotation is

A

$\dfrac{1}{2} MR^2$

B

$\dfrac{1}{4} MR^2$

C

$\dfrac{1}{8} MR^2$

D

$\sqrt{2} MR^2$

3
IIT-JEE 2000
+2
-1

A thin wire of length $L$ and uniform linear mass density $\rho$ is bent into a circular loop with centre at $O$ as shown. The moment of inertia of the loop about the axis $XX'$ is:

A

$\frac{\rho L^3}{8\pi^2}$

B

$\frac{\rho L^3}{16\pi^2}$

C

$\frac{5\rho L^3}{16\pi^2}$

D

$\frac{3\rho L^3}{8\pi^2}$

EXAM MAP
Medical
NEET