This set of Strength of Materials Problems focuses on “Moment of Inertia of Section”.

1. What is the moment of inertia of a circular section?

a) πD^{4}/64

b) πD^{3}/32

c) πD^{3}/64

d) πD^{4}/32

View Answer

Explanation: The moment of inertia of a circular section is πD

^{4}/64.

2. What is the moment of inertia of a rectangular section about an horizontal axis through C.G?

a) bd^{3}/6

b) bd^{2}/12

c) b^{2}d^{2}/12

d) bd^{3}/12

View Answer

Explanation: The moment of inertia of a rectangular section about an horizontal axis through C.G is bd

^{3}/12.

3. What is the moment of inertia of a rectangular section about an horizontal axis passing through base?

a) bd^{3}/12

b) bd^{3}/6

c) bd^{3}/3

d) bd^{2}/3

View Answer

Explanation: The moment of inertia of a rectangular section about an horizontal axis passing through base is bd

^{3}/3.

4. What is the moment of inertia of a triangular section about the base ?

a) bh^{2}/12

b) bh^{3}/12

c) bh^{3}/6

d) bh^{2}/6

View Answer

Explanation: The moment of inertia of a triangular section about the base is bh

^{3}/12.

5. What is the moment of inertia of a triangular section about an axis passing through C.G. and parallel to the base?

a) bh^{3}/12

b) bh^{3}/24

c) bh^{3}/36

d) bh^{3}/6

View Answer

Explanation: The moment of inertia of a triangular section about an axis passing through C.G. and parallel to the base is bh

^{3}/36.

6. What will be the moment of inertia of a circle in cm4 of diameter is 10cm ?

a) a340

b) 410

c) 460

d) 490

View Answer

Explanation: The moment of inertia of a circle is = πD

^{4}/64

= 491.07 cm

^{4}.

7. What will be the moment of inertia of the given rectangle about an horizontal axis passing through the base?

a) 1500 mm^{4}

b) 1650 mm^{4}

c) 1666 mm^{4}

d) 1782 mm^{4}

View Answer

Explanation: The moment of inertia of a rectangular section about an horizontal axis passing through base = bd

^{3}/3

= 5x10x10x10/3

= 1666.66 mm

^{4}.

8. What will be the moment of inertia of the given rectangular section about an horizontal axis through C.G. ?

a) 350 mm^{4}

b) 379mm^{4}

c) 416mm^{4}

d) 500mm^{4}

View Answer

Explanation: The moment of inertia of a rectangular section about an horizontal axis through C.G = bd

^{3}/12

= 5x10x10x10/12

= 416.67 mm

^{4}.

9. What will be the moment of inertia of the given triangle about the base?

a) 20.33 mm^{4}

b) 21.33 mm^{4}

c) 24.33 mm^{4}

d) 22.33 mm^{4}

View Answer

Explanation: The moment of inertia of a triangular section about the base = bh

^{3}/12.

= 4x4x4x4/12

= 21.33 mm

^{4}.

10. What will be the moment of inertia of the given triangle about an axis passing through C.G and parallel to base?

a) 6.1 mm^{4}

b) 7.1 mm^{4}

c) 8.1 mm^{4}

d) 7.56 mm^{4}

View Answer

Explanation: The moment of inertia of a triangular section about an axis passing through C.G. and parallel to the base = bh

^{3}/36.

= 4x4x4x4/36

= 7.11 mm

^{4}.

11. What will be the difference between MOI of two triangle sections is in 1st , MOI is taken about its base and in 2nd MOI is taken about its centroid ?

a) bh^{3}/12

b) bh^{3}/18

c) bh^{3}/36

d) bh^{3}/24

View Answer

Explanation: The moment of inertia of a triangular section about the base is bh

^{3}/12

The moment of inertia of a triangular section about an axis passing through C.G. is bh

^{3}/36

So the difference = bh

^{3}/12 – bh

^{3}/36 = bh

^{3}/18 .

**Sanfoundry Global Education & Learning Series – Strength of Materials. **

To practice all areas of Strength of Materials Problems, __here is complete set of 1000+ Multiple Choice Questions and Answers__.