## Essential University Physics: Volume 1 (4th Edition)

$170N$
As the bracket is in equilibrium hence $\sum \tau_{pivot}=0$ $\implies F_{sx}\times 7.2+Mg\times 9+mg\times 28=0$ This simplifies to: $F_{sx}=-\frac{9Mg+28mg}{7.2}$ We plug in the known values to obtain: $F_{sx}=\frac{(9\times 0.85+28\times 4.2)\times 9.8}{7.2}=-170N$ The negative sign shows that the force is in the opposite direction.