Stop a rotating plane using external force

I have a plane which rotates using rigidbody.MoveRotation(). I want the rotation to slow down and ultimately stop after a certain time.

On the screen I want to show that the Plane stopped rotating because it kept hitting another object.

How can I do this? Please help.

You can adjust the rigidbody's angular drag. This will slow down and ultimately stop the rotation of your object. I don't know what you mean with your second question. How to print something to the screen?