A 200 mm × 300 mm plate has a circular hole of diameter 40 mm on its vertical centre line, with its centre 210 mm above the bottom edge. Find the height ȳ of the centroid above the bottom edge.
Centroid & second moment of area worksheet with answers
Find the height ȳ of the centroid of the T-section above its bottom edge.
A channel section lies with its open side up: a base plate 260 mm wide with two upright legs, 180 mm high overall. Base and legs are all 8 mm thick. Find its second moment of area Ix about the horizontal axis x through its centroid.
Find the second moment of area Ix of the T-section about the horizontal axis x through its centroid.
A 200 mm × 200 mm plate has a rectangular cut-out 80 mm wide and 40 mm high, centred on the vertical centre line with its centre 130 mm above the bottom. Find the second moment of area Ix about the horizontal axis through the centroid.
The T-section is used as a beam with the flange on top and carries a sagging bending moment of 50 kN·m. Find the size of the bending stress σtop at the top edge.
Answer key
- 1. ȳ = 148.7 mm
- 2. ȳ = 126.4 mm
- 3. Ix = 16.39 × 10⁶ mm⁴
- 4. Ix = 31.87 × 10⁶ mm⁴
- 5. Ix = 129.8 × 10⁶ mm⁴
- 6. σtop = 68.52 MPa
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