For an object that can be modeled as a point particle, the object is in static equilibrium if all the forces acting on the object cancel each other out.  But with an extended object, where the forces act on the object also matters.  For an extended object to be in static equilibrium, both the forces and the torques generated by those forces must cancel out.  This is true for the two-dimensional problems we have looked at in this section, where all the forces acting on the extended object are confined to a plane.  But this is also true in the real world, where those forces can point in any of three dimensions.  Though it is not the focus of this class, many of you will take additional courses where you will work static equilibrium problems in three dimensions.  Even in these more complicated scenarios, all the forces and torques acting on an object need to cancel out for an object to be in static equilibrium.