A solid circular bar has diameter D = 280 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 100 mm × 200 mm plate has a circular hole of diameter 50 mm on its vertical centre line, with its centre 140 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.
The T-section is used as a beam with the flange on top and carries a sagging bending moment of 40 kN·m. Find the bending stress σbottom at the bottom edge.
A welded I-section has a top flange 120 × 14 mm, a web 210 mm high and 10 mm thick, and a bottom flange 210 × 22 mm (width × thickness). Find its second moment of area Ix about the horizontal axis x through its centroid.
Answer key
- 1. Ix = 301.7 × 10⁶ mm⁴
- 2. ȳ = 68.33 mm
- 3. Ix = 62.88 × 10⁶ mm⁴
- 4. Ix = 11.48 × 10⁶ mm⁴
- 5. σbottom = 338.6 MPa
- 6. Ix = 76.77 × 10⁶ mm⁴
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