Find the height ȳ of the centroid of the T-section above its bottom edge.
Centroid & second moment of area worksheet with answers
A solid circular bar has diameter D = 160 mm. Find its second moment of area Ix about a diameter.
A 100 mm × 200 mm plate has a circular hole of diameter 60 mm on its vertical centre line, with its centre 120 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 50 kN·m. Find the bending stress σbottom at the bottom edge.
A 120 mm × 150 mm plate has a rectangular cut-out 30 mm wide and 30 mm high, centred on the 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.
Answer key
- 1. ȳ = 182.7 mm
- 2. Ix = 32.17 × 10⁶ mm⁴
- 3. Ix = 64.71 × 10⁶ mm⁴
- 4. Ix = 30.38 × 10⁶ mm⁴
- 5. σbottom = 264.1 MPa
- 6. Ix = 33.2 × 10⁶ mm⁴
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