Where is rotational dynamics???????

In dynamics of translational motion, we are concerned about what causes translational motion (force) and what opposes change in motion (mass or inertia) and corresponding principles related to conservation of linear momentum and conservation of mechanical energy.

In Rotational Dynamics, we are concerned about what change in rotational motion (Torque) and what opposes this change in rotational motion (moment of inertia).  We learn conservation of angular momentum (in the absence of external torque angular momentum of system of particles must be conserved).  A body in rotational motion has rotational kinetic energy.  Hence conservation energy must include rotational kinetic energy also.  We also learn about rolling of spherical or cylindrical objects on the surface of other objects and the role of friction played in rolling etc..

The rotational dynamics concepts are important in the design of mechine parts (eg design of transmission system in an automobile), navigation systems etc., basically wherever rotating bodies are involved.