A circular tube has outside diameter D = 240 mm and inside diameter d = 204 mm. Find its second moment of area Ix about a diameter.
Centroid & second moment of area worksheet with answers
Find the height ȳ of the centroid of the T-section above its bottom edge.
A 200 mm × 150 mm plate has a circular hole of diameter 30 mm on its vertical centre line, with its centre 52.5 mm above the bottom. Find the second moment of area Ix about the horizontal axis through the centroid.
Find the second moment of area Ix of the T-section about the horizontal axis x through its centroid.
A symmetric I-section has flanges 190 mm wide and 22 mm thick, an overall depth of 400 mm and a web 10 mm thick. It carries a bending moment of 40 kN·m about the axis x. Find the size of the bending stress σj at the junction of the web and the top flange.
A welded I-section has a top flange 160 × 16 mm, a web 220 mm high and 16 mm thick, and a bottom flange 190 × 14 mm (width × thickness). Find its second moment of area Ix about the horizontal axis x through its centroid.
Answer key
- 1. Ix = 77.85 × 10⁶ mm⁴
- 2. ȳ = 120.5 mm
- 3. Ix = 55.84 × 10⁶ mm⁴
- 4. Ix = 5.754 × 10⁶ mm⁴
- 5. σj = 21.16 MPa
- 6. Ix = 86.34 × 10⁶ mm⁴
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