College Physics (7th Edition)

Net force = 0 So, $m_{1}g+m_{2}g+m_{3}g=N$ $N=1.96N$ Balancing net torque = $m_{1}g\times100+m_{2}g\times80+m_{3}g\times15-50N=98-98=0$ Hence, net torque about x = 100 cm is zero. Hence, proved.
Net force = 0 So, $m_{1}g+m_{2}g+m_{3}g=N$ $N=1.96N$ Balancing net torque = $m_{1}g\times100+m_{2}g\times80+m_{3}g\times15-50N=98-98=0$ Hence, net torque about x = 100 cm is zero. Hence, proved.