Find the height ȳ of the centroid of the T-section above its bottom edge.
Centroid & second moment of area worksheet with answers
A rectangular section has width b = 300 mm and height h = 375 mm. Find its elastic section modulus Sx for bending about the horizontal centroidal axis x.
Find the second moment of area Ix of the T-section about the horizontal axis x through its centroid.
A 150 mm × 300 mm plate has a circular hole of diameter 60 mm on its vertical centre line, with its centre 180 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 15 kN·m. Find the size of the bending stress σtop at the top edge.
The T-section is used as a beam with the flange on top and carries a sagging bending moment of 30 kN·m. Find the bending stress σbottom at the bottom edge.
Answer key
- 1. ȳ = 132.2 mm
- 2. Sx = 7031 × 10³ mm³
- 3. Ix = 65.12 × 10⁶ mm⁴
- 4. Ix = 334.1 × 10⁶ mm⁴
- 5. σtop = 25.02 MPa
- 6. σbottom = 153.2 MPa
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