1.A subsystem is in equilibrium if the combined effect of all external forces produces zero translational and rotational acceleration.
If there is to be no translational acceleration, the forces must sum to zero: ΣF=0
If there is to be no rotational acceleration, the moments must sum to zero: ΣM|o =0
where O is any point on or off the body.
Force and moment summation should include all external forces acting directly on the subsystem,namely, the forces drawn in the FBD.
If there is to be no translational acceleration, the forces must sum to zero: ΣF=0
If there is to be no rotational acceleration, the moments must sum to zero: ΣM|o =0
where O is any point on or off the body.
Force and moment summation should include all external forces acting directly on the subsystem,namely, the forces drawn in the FBD.