While you are applying the force, it won't necessarily rotate about its CM. After you have let go of it, it will do so. What's the difference?Horvath Bela said:
A long rod will rotate on a frictionless surface due to the principle of conservation of angular momentum. This means that the total angular momentum of the system remains constant, so any changes in the rotation of the rod must be counterbalanced by changes in the rotation of the surface.
A frictionless surface allows for the rotation of a long rod to continue indefinitely without any external forces slowing it down. This is because there is no friction to create a torque that would oppose the rotation of the rod.
In theory, yes. As long as there are no external forces acting on the system, the long rod will continue to rotate on a frictionless surface indefinitely due to the conservation of angular momentum.
The length of the rod does not have a direct effect on its rotation on a frictionless surface. However, a longer rod will have a larger moment of inertia and therefore require more torque to change its rotation compared to a shorter rod.
If friction is present on the surface, it would create a torque that opposes the rotation of the long rod. This would cause the rotation to slow down and eventually come to a stop, as some of the angular momentum is dissipated as heat due to the friction.