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__.

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