Two uniform planks, each of mass m = 4.71 kg and length L = 2.07 m, are connected by a hinge at the top and by a chain of negligible mass attached at their centers, as shown in the figure. The assembly will stand upright, in the shape of an A, on a frictionless surface without collapsing. If the chain has the length 0.73 m, find each of the following:
a) the absolute value of the tension in the chain,

b) the absolute magnitude of the force on the hinge of each plank

Question

Two uniform planks, each of mass m = 4.71 kg and length L = 2.07 m, are connected by a hinge at the top and by a chain of negligible mass attached at their centers, as shown in the figure. The assembly will stand upright, in the shape of an A, on a frictionless surface without collapsing. If the chain has the length 0.73 m, find each of the following: 
a) the absolute value of the tension in the chain,

b) the absolute magnitude of the force on the hinge of each plank

anonymous · Answer

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20.65 degree is from sin^-1(0.365/1.035)

F =ma = 2.07(9.8)=20.286N
horizontal force = 20.286N sin 20.65 = 7.154N

i think the tension of the chain is 7.154N*2=14.308N