- **External Forces Define Equilibrium**
The equilibrium of a rigid body is determined solely by the external forces acting on the body. These external forces can include gravitational forces, applied forces, and any other forces acting on the body from the surroundings.
- **Support Reactions Cancel Out Rotation**
The support reactions, such as normal forces and frictional forces, play a crucial role in ensuring that the body remains in equilibrium. However, these support reactions primarily cancel out the rotation part of the body's equilibrium.
- **Balancing Rotation and Translation**
When analyzing the equilibrium of a rigid body, it is essential to consider both the translational equilibrium (balance of forces) and rotational equilibrium (balance of torques). The support reactions contribute to canceling out the net torque acting on the body, allowing it to remain in rotational equilibrium.
- **Net Torque and Support Reactions**
Support reactions can counteract the net torque produced by external forces, preventing the body from rotating. This is crucial in maintaining the stability of the body and ensuring that it remains in equilibrium.
- **Complete Equilibrium Condition**
In summary, for a rigid body to be in complete equilibrium, the external forces must be balanced in both translation and rotation. The support reactions play a significant role in canceling out the rotational component of the equilibrium, allowing the body to remain stable.