10 QA on moment of inertia | Learn Physics

10 Question-Answer on moment of inertia

1.       Moment of inertia of a uniform circular disc about a diameter is I. Its moment of inertia about an axis └ to its plane and passing through a point on its rim will be:

(a)    5 I

(b)   3 I

(c)    6 I

(d)   4 I

Ans :( c)

2.       The moment of inertia of a body about a given axis is 1.2 kg m² Initially, the body is at rest .In order to produce a rotational kinetic energy of 1500 joule, an angular acceleration of 25 radian/s² must be applied about that axis far a duration of :

(a)    4 sec

(b)   2 sec

(c)    8 sec

(d)   10 sec

Ans: ( b)

3.       A hoop o mass M and radius R is suspended on a peg in a wall. Its moment of inertia about the peg is :

(a)    2MR²

(b)   MR²

(c)    MR²/2

(d)   3 MR²/2

Ans: ( a)

4.       The diameter of a flywheel is increased by 1%. Increase in its moment of inertia about the central axis is:

(a)    1%

(b)   0.5%

(c)    2%

(d)   4%

Ans: (c)

5.       Two bodies of moment of inertia I₁ and I₂ (I₁> I₂) have equal angular moments. If E₁ , E₂ are their kinetic energies of rotation , then

(a)    E₁ >E₂

(b)   E₁=E₂

(c)    E₁<E₂

(d)   Cannot be said

Ans: ( c)

6.       The moment of inertia of two spheres of equal masses about their diameters is equal. If one of them is solid and other is hollow, the ratio of their radii is:

(a)    √3 : √5

(b)   3 : 5

(c)    √5 : √3

(d)   5 : 3

Ans: (c)

7.       The moment of inertia of a body depends on its

(a)    Volume

(b)   Energy

(c)    Surface area

(d)   Mass and size

Ans: ( d)

8.       The spokes used in the wheel of a bicycle increases its

(a)    moment of inertia

(b)   tangential velocity

(c)    centripetal acceleration

(d)   total momentum

Ans: ( a)

9.       Which of the following plays the same role in rotational motion as is played by the mass in translator motion:

(a)    Velocity

(b)   Force

(c)    moment of inertia

(d)   mass.

Ans: ( c )

10.       The moments of inertia of a cube will be minimum about an axis which:

(a)    By spinning them using equal torques

(b)   By determining their moment of inertia

(c)    By rolling them down an inclined plane

(d)   By anyone of these methods.

Ans: (d)