A 85 kg scaffold is 6.4 m long. It is hanging with two wires, one from each end. A 440 kg box sits 1.4 m from the left end. What is the tension in the left hand side wire?(g = 9.8 m/s2)Answer in newtons
85kg. is 42.5kg each cable. 6.4/1.4 = 4.571:1 ratio. Add both sides. (440/5.571) x 4.571 = 361kg. Add the 42.5, = 403.52kg. 403.52 x 9.8 = 3,954.5N tension in left cable.
scaffold mg = 85 x 9.8 = 833 N box mg = 440 x 9.8 = 4312 N left hand wire = ((833/2) x 6.4) + (4312 x (6.4 - 1.4)) = 24225.6 24225.6 = 6.4 x left hand tension 24225.6/6.4 = 3785.25 N (answer)
Sum of Moments around right wire: T(6.4)=9.8*(440(5)+85(3.2)) T= 3785N
