The three identical bars, each weighing 10.8 lb, are connected by the two freely pinned links of negligible weight and are resting on a smooth horizontal surface. Calculate the initial acceleration a of the center of the middle bar when the 7.8-lb force is applied to the connecting link as shown. 7.8 lb Answer: a = i ft/sec2

The cross section of a wood beam carries a bending moment M of magnitude 20R lb.-in. acting at 100 to the horizontal. Determine(a)the angle between the neutral axis and the horizontal; and (b) the maximum bending stress acting on the cross section. Note: ( R=990)

Situation # 3: Assume that the frame in figure C is pin-connected at points A, B, and C, and that joints D and E are fixed-connected, solve the following: 8. Bx (in kN) 9. By (in kN) 10. Cx (in kN) 11. Cy (in kN) 3 k/ft B 6 ft D 1.5 k/ft 10 ft 18 ft -18 ft Figure C E

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