NEET Physics Moment of Inertia and Rotational K E MCQs Set A

Question. Moment of inertia does not depend upon
(a) point of application of force
(b) None of these
(c) axis of rotation
(d) distribution of mass

Answer: A

Question. Moment of inertia of a circular wire of mass M and radius R about its diameter is
(a) MR²/2
(b) MR²
(c) 2MR²
(d) MR²/4

Answer: A

Question. Which of the following has the highest moment of inertia when each of them has the same mass and the same outer radius
(a) a ring about its axis, perpendicular to the plane of the ring
(b) a disc about its axis, perpendicular to the plane of the ring
(c) a solid sphere about one of its diameters
(d) a spherical shell about one of its diameters

Answer: A

Question. Radius of gyration of a body depends upon
(a) axis of rotation
(b) translational motion
(c) area of the body
(d) shape of the body

Answer: A

Question.  If two circular discs A and B are of same mass but of radii r and 2r respectively, then the moment of inertia of A is
(a) 1/4 that of B
(b) twice that of B
(c) the same as that of B
(d) four times that of B

Answer: A

Question. For a given mass and size, moment of inertia of a solid disc is
(a) less than that of a ring
(b) equal to that of a ring
(c) depend on the material of ring and disc
(d) more than that of a ring

Answer: A

Question. Assertion : If polar ice melts, days will be longer.
Reason :    Moment of inertia decreases and thus angular velocity increases
(a) Assertion is correct, reason is incorrect
(b) Assertion is incorrect, reason is correct
(c) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
(d) Assertion is correct, reason is correct; reason is a correct explanation for assertion.

Answer: A

Question.  Of the two eggs which have identical sizes, shapes and weights, one is raw, and other is half boiled. The ratio between the moment of inertia of the raw to the half boiled egg about central axis is
(a) greater than one
(b) not comparable
(c) one
(d) less than one

Answer: A

Question. One solid sphere A and another hollow sphere B are of same mass and same outer radii, Their moments of inertia about their diameters are respectively I_A and I_B, such that
(a) I_A < I_B
(b) I_A = I_B
(c) I_A > I_B
(d) None of these

Answer: B

Question.  A wheel having moment of inertia 2 kg-m² about its vertical axis, rotates at the rate of 60 rpm about this axis, The torque which can stop the wheel’s rotation in one minute would be
(a) 0.21 Nm
(b) 0.55 Nm
(c) 0.83 Nm
(d) 1.12 Nm

Answer: A

Question.  The moment of inertia of a thin uniform rod of mass M and length L about an axis passing through its midpoint and perpendicular to its length is I₀. Its moment of inertia about an axis passing through one of its ends and perpendicular to its length is
(a) I₀ + ML²/4
(b) I⁰ + ML²
(c) I₀ + 2ML²
(d) None of these

Answer: A

Question.  Point masses 1, 2, 3 and 4 kg are lying at the points (0, 0, 0), (2, 0, 0), (0, 3, 0) and (–2, –2, 0) respectively. The moment of inertia of this system about X-axis will be
(a) 43 kg m²
(b) 34 kg m²
(c) 27 kg m²
(d) 72 kg m²

Answer: A

Question.  A solid cylinder of mass 50 kg and radius 0.5 m is free to rotate about the horizontal axis. A massless string is wound round the cylinder with one end attached to it and other hanging freely. Tension in the string required to produce an angular acceleration of 2 revolutions s^{– 2} is
(a) 157 N
(b) 78.5 N
(c) 50 N
(d) 25 N

Answer: A

Question. The restoring force per unit area is known as
(a) stress
(b) plasticity
(c) elasticity
(d) strain

Answer: A

Question. What is the phenomenon of temporary delay in regaining the original configuration by an elastic body, after the removel of a deforming force?
(a) Elastic after effect
(b) Elasticity
(c) Elastic fatigue
(d) Plasticity

Answer: A