Question

A man spinning in free space changes of his body e.g by spreading his arms and curling up. By doing this, he can change his 1) moment of inertia 2) angular momentum 3) angular velocity 4) rotational kinetic energy in this Which of the following is correct?

Answer 1

When a man spinning changes his position of body by spreading arms or curling up his angular momentum does not change as there is no external torque, by conservation of angular momentum. But his moment of inertia, angular velocity changes.  

So he can change his  moment of inertia, angular velocity and rotational kinetic energy.