Question

Which of the following is the necessary and sufficient criterion for a body to be called rigid?

• A. The body does not move at all with respect to any stationery frame.
• B. All the points of the body move with the same speed.
• C. The relative position of any two point particles of the body do not change as time passes.
• D. The body does not respond to any amount of external force applied in any way.

Answer 1

The correct option is C

The relative position of any two point particles of the body do not change as time passes.

Basic criteria of any body/object to be called rigid under given circumstances is if any amount of force does not change the relative positions of any constituent particles of the body with respect to each other.