a uniform rod 100cm long and weighing 50N is supported on a horizontal position on a fulcrum which weights of 80N and 100N suspended on its ends. compute the position of the fulcrum

2 answers

fulcurm force: sum of weights: 230N

sum moments about the 100N end

50N*50cm+80N*100cm-230L=0

solve for L, the distance from the 100N end
The word "which" in your question should probably be "with". Let x be the distance, in cm, of the fulcrum from the end with the 80 N weight.

Since there is equilibrium, the total moment about the fulcrum is zero, and
80 x - 100(100 - x) + 50*(50 - x) = 0
130 x = 10,000 -2500 = 7500
x = 57.7 cm