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Question Bank No: 2

1. A circular loop of wire of mass 'm' and radius 'r' is making 'n' revolutions per second about a point on the rim. The kinetic energy of rotation of the ring is

a)		$8 π^{2} m r^{2} n^{2}$
b)		$4 π^{2} m r^{2} n^{2}$
c)		$2 π^{2} m r^{2} n^{2}$
d)		$π^{2} m r^{2} n$

2. Four spheres each of diameter '2a' and mass m are placed at the corners of a square of side 'b'. The moment of inertia of the system about any side of the square will be

a)		(8/5) $m a^{2} + m b^{2}$
b)		(8/5) $m a^{2} + 2 m b^{2}$
c)		(8/5) $m a^{2} + 4 m b^{2}$
d)		(8/5) $m a^{2} + 16 m b^{2}$

3. Two solid spheres each of mass M and diameter R are connected by a light rod of length R. The moment of inertia of the system about a vertical axis passing through the centre of one of the spheres and perpendicularto the line joining the spheres is

a)		(21/5) $M R^{2}$
b)		(24/3) $M R^{2}$
c)		(2/5) $M$ $R^{2}$
d)		(7/5) $M R^{2}$

4. A body of mass 1 kg is moving with a constant velocity 3i - 4j in the X-Y plane. At a certain instant it is at a point (0,4) measured in metres. The angular momentum about the origin is (in $kg m^{2} s^{- 1}$ )

a)		12 along the Z axis
b)		5 along the Z axis
c)		16 along the X axis
d)		16 along the Z axis

5. The moment of inertia of a ring about an axis passing through its rim and perpendicular to its plane bears the following ratio with the moment of interia of the ring about a diameter

a)		4 : 1
b)		1 : 4
c)		3 : 1
d)		2 : 1

6. A circular disc of mass m and radius r is rolling on a horizontal table with uniform velocity v. The energy of the disc is

a)		(1/2) $m v^{2}$
b)		(1/4) $m v^{2}$
c)		(3/4) $m v^{2}$
d)		$m v^{2} / r$