the force acted on the beam after 3 metres, therefore BM is 8x3 = 24KNm. Therefore, compresive stress = 24000x0.096/102x10^-6 = 22588235Pa = 22.6 MPa. That was my answer, can u tell me how it's wrongQ20 should be A. Its a tricky question. You need to calculate 'y' which is 96, as the top half of the beam undergoes compressive stress. 'm' can be calculated by drawing up a basic SFD and BMD, which is 12kNm. Plug it into the bending stress formula, and it would be approximately 11.3MPa. The given area is useless information. Q10 answer:B would make some sense, as you'd average out the radii to get 16.5, which is the radius along the neutral axis. IDK about 14, I put down B for that.
EDIT: argg, i forgot it was 4x3 = 12KNm, dammit should have made a diagram -.- you're right