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Q1 The thin-walled cross-section in Figure 1 is made of an alloy sheet of constant thickness t with a 90 corner of radius R and two flanges of length 2Reach. The cross-section is oriented at 45% with respect to the XY plane and is therefore symmetric about the X axis. The origin of the arc-length s is placed at the top-right corner as shown. It should be noted that t < R, so thin wall assumptions (and line integrals) must be used throughout this question. =0 2 R 51 R450 52 45° Figure 1: A symmetric thin-walled open section. (a) Demonstrate that the cross-sectional area is A = (4 + ) +R. (3 marks) (b) Demonstrate that the first moment of area about the Y axis is Qyr = -VER (3 marks) (c) Demonstrate that the horizontal distance between the Y axis and the shear centre is vZtR/68 +97 ex = 12 (10 marks)