Consider the Fig. 9.3,

Let us consider the reactive forces are Ax, Ay and N on two rigid bodies. Both these bodies are considered to be in equilibrium so there will be no work.

If P and Q acts on the bodies to do virtual work, the internal forces will act as reactive forces to cancel the total work.

**Links of Previous Main Topic:-**

- Introduction concept of equilibrium of rigid body
- Friction introduction
- Introduction about distributed forces
- Area moments of inertia in rectangular and polar coordinates
- Mass moment of inertia introduction
- Work done by force
- Sign convention of mechanical work

**Links of Next Mechanical Engineering Topics:-**