*7 Example 2 0 100kN 0 0 A B 4m 10m 240 kN-m c.g.of shaded area EI c.g.of total area M 6396/E1 639.6kN.m2 4 =1.33m 10+6=5.33m 10 El 3 3 A= 240 639%kN·m3 -2 10×5.33 El 0c=64- △c=64 a-At El 0%s b d -0s =0-0 6m 450 kN:m EI 1 1 300kN·m 600 kN.m 8m 2m EI 4m 丽