Question

What is a perfectly plastic body? Give one example.

Answer 1

The property of the material body by virtue of which it does not regain its original configuration when the external force removed is called plasticity. Before going towards a perfectly plastic body we should learn about deforming force.

Complete step by step solution:
Deforming force: If a force applied on a body produces a change in the normal positions of the molecules of the body, which results in a change in the configuration of the body either in lengths, volume or shape, then the force applied is called deforming force. Thus, a deforming force is the one which when applied changes the configuration of the body.
Perfectly elastic body: A body which does not regain its original configuration at all on the removal of the deforming force, however small the deforming force may be, is called a perfectly plastic body. Putty, mud and paraffin wax are examples of the nearly perfect bodies. In fact , nothing is perfectly plastic or perfectly elastic . Only the degree of elasticity or plasticity differs from body to body.
The body which does not have the property of opposing the deforming force, is known as a plastic body.
The bodies which remain in deformed state even after removal of the deforming force are defined as plastic bodies.

Note: A body is said to be rigid if the relative position of its constituent particles remains unchanged when external deforming forces are applied to it. The nearest approach to a rigid body is diamond or carborundum.