The theory was based on a perfectly rigid body, but Earth is slightly elastic.

Even the stiffest of rock is not perfectly rigid.

Suddenly she turned and faced the wall behind her, and stood perfectly rigid for a moment.

In a vacuum, a perfectly rigid disc on an absolutely hard surface would roll forever.

He stood for a long time perfectly rigid.

Inside, still strapped down, helmet on and sitting perfectly rigid, was General Jones.

In addition, there will usually be torque, plus other effects if the wire is not perfectly rigid.

But pride and common sense kept her perfectly rigid.

And with a perfectly rigid face, he signed it: Pirx, first navigator.

He held himself perfectly rigid, knowing that any upset in the alien's balance would be disastrous.