Find the height ȳ of the centroid of the T-section above its bottom edge.
Centroid & second moment of area worksheet with answers
A hollow rectangular (box) section has outer width B = 160 mm, outer height H = 350 mm and a uniform wall thickness t = 16 mm. Find its second moment of area Ix about the horizontal centroidal axis x.
A circular tube has outside diameter D = 170 mm and inside diameter d = 138 mm. Find its radius of gyration r about the horizontal centroidal axis.
A hollow rectangular (box) section has outer width B = 300 mm, outer height H = 375 mm and a uniform wall thickness t = 14 mm. Find its radius of gyration r about the horizontal centroidal axis.
A welded I-section has a top flange 180 × 10 mm, a web 370 mm high and 16 mm thick, and a bottom flange 290 × 10 mm (width × thickness). Find its second moment of area Ix 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 30 kN·m. Find the bending stress σbottom at the bottom edge.
Answer key
- 1. ȳ = 182.6 mm
- 2. Ix = 228.7 × 10⁶ mm⁴
- 3. r = 54.74 mm
- 4. r = 143.2 mm
- 5. Ix = 233.1 × 10⁶ mm⁴
- 6. σbottom = 125.5 MPa
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