Find the height ȳ of the centroid of the T-section above its bottom edge.
Centroid & second moment of area worksheet with answers
A 240 mm × 240 mm plate has a circular hole of diameter 50 mm whose centre is 60 mm from the left edge (at mid-height). Find the distance x̄ of the centroid from the left edge.
Find the second moment of area Ix of the T-section about the horizontal axis x through its centroid.
A channel section lies with its open side up: a base plate 200 mm wide with two upright legs, 200 mm high overall. Base and legs are all 14 mm thick. Find the height ȳ of the centroid above the bottom edge.
The T-section is used as a beam with the flange on top and carries a sagging bending moment of 25 kN·m. Find the size of the bending stress σtop at the top edge.
A welded I-section has a top flange 130 × 16 mm, a web 190 mm high and 10 mm thick, and a bottom flange 300 × 18 mm (width × thickness). Find its second moment of area Ix about the horizontal axis x through its centroid.
Answer key
- 1. ȳ = 157.7 mm
- 2. x̄ = 122.1 mm
- 3. Ix = 4.557 × 10⁶ mm⁴
- 4. ȳ = 72.03 mm
- 5. σtop = 191.4 MPa
- 6. Ix = 73.52 × 10⁶ mm⁴
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