POLAR & MOMENT OF INERTIA MULTIPLE CHOICE QUESTIONS (MCQ) WITH ANSWERS
POLAR & MOMENT OF INERTIA
MULTIPLE CHOICE QUESTIONS
(MCQ) WITH ANSWERS
MCQ increase the clarity and
understanding. Moment of inertia plays
its role in bending. Higher value resists
bending. Highest value is for Ishaped
cross section. Polar moment of inertia is
important for circular motion as in
shafts. Higher value of polar moment
of inertia reduces shear stress and
distortion.
Fig. Parallel Axis Theorem (I_{AB} =I_{NA} +Ah^{2})
Fig. Perpendicular Axis Theorem (I_{zz}=J=I_{XX}+I_{YY})

Polar moment of inertia is about

Neutral axis

Centroid axis

Neutral fiber

None
ANS: (b)

Polar moment of inertia is used in

Beams

Columns

Shafts

None
ANS: (c )

Polar moment of inertia is determined with

Parallel axis theorem

Perpendicular axis theorem

Both parallel & perpendicular axis theorems

None
ANS: (b)

Polar moment of inertia is given by

Firstly I_{xx} –I_{yy}

Secondly I_{xx} + I_{yy}

Thirdly I^{2}_{xx} +I^{2}_{yy}

None
ANS: (b)

Polar moment of inertia of a rectangular cross section is

(1/12)bh(b^{2}+h^{2})

(1/12)bh(b^{3}+h^{3})

(1/12)(bh)(b^{4}+h^{4})

None
ANS: (a)

Polar moment of inertia of a circular section is

(π/64) d^{3}

(π/64) d^{4}

(π/32) d^{4}

None
ANS: ©

Higher polar moment of inertia gives

High distortion

Less distortion

Medium distortion

None
ANS: (b)

Polar moment of inertia is used in

Rectilinear motion

Planar motion

Circular motion

None
ANS: (c )

Why is it called polar moment of inertia?

It is about a line in the crosssection

About a point in the crosssection

About a parallel axis in the cross –section

None
ANS: (b)

Which crosssection is used maximum with polar moment of inertia?

Rectangular

Square

Circular

None
ANS: (c )

Symbol for polar moment of inertia

I

J

Z

None
ANS: (b)

Units of polar moment of inertia

Firstly mm^{3}

Secondly mm^{2}

Thirdly mm^{4}

None
ANS: (c )

For a circular section, polar moment of inertia is

4 I_{xx}

3 I_{xx}

2 I_{xx}

None
ANS: (c )

For a rectangular section, polar moment of inertia is

Firstly 2 I_{xx}

Secondly 2 I_{yy}

Thirdly 2 I_{zz}

_{None}
_{ANS: }(d)
15. Moment of inertia is for a

3 dimensional body

2 dimensional plain figure

1 dimensional line

None
ANS: (b)

Symbol for moment of inertia is

J

I

Z

None
ANS: (b)

Units for moment of inertia is

Firstly mm

Secondly mm^{2}

Thirdly mm^{3}

None
ANS: (d)

Moment of inertia of a crosssection about xx axis is

Firstly ∫dA y^{2}

Secondly ∫dA x^{2}

Thirdly ∫dA z^{2}

None
ANS: (a)

Moment of inertia for a rectangular cross section about xxaxis, width b and depth d is

Firstly I_{xx} = (1/12) bd^{4}

Secondly I_{xx} = (1/12) bd^{2}

Thirdly I_{xx} = (1/12) bd^{3}

None
ANS: ©

Moment of inertia for a square cross section, each side is ‘a’

Firstly I_{xx} =I_{yy} = (1/12) a^{4}

Secondly I_{xx} =I_{yy} = (1/12) a^{3}

Thirdly I_{xx} =I_{yy} = (1/12) a^{2}

None
ANS: (a)

Moment of inertia for a circular solid cross section

Firstly I_{xx} =I_{yy} = (π/64) d^{3}

Secondly I_{xx} =I_{yy} = (π/64) d^{2}

Thirdly I_{xx} =I_{yy} = (π/64) d^{4}

(d)None
ANS: (c )

Moment of inertia for a circular hollow cross section

(a) I_{xx} =I_{yy} = (π/32)[ d_{o}^{4} – d_{i}^{4} ]

(b) I_{xx} =I_{yy} = (π/64)[ d_{o}^{4} – d_{i}^{4} ]

© I_{xx} =I_{yy} = (π/16)[ d_{o}^{4} – d_{i}^{4} ]

(d)None
ANS: (b)
23. Use of moment of inertia is in

Torsion

Bending

Tension

None
ANS: (b)
24. Larger value of moment of inertia reduces

Distortion

Deformation

Both distortion & deformation

None
ANS: (b)
25. Which is best section with same value of cross sectional area?

Rectangular

Circular

Elliptical

None
ANS: (d)
26. Which is best section with same value of cross sectional area?

Rectangular

Circular

Isection

None
ANS: (c)
https://www.mesubjects.net/wpadmin/post.php?post=7685&action=edit Moment of inertia