Question

Distinguish between elasticity and plasticity.

Answer 1

Hint: Solids show different properties. Here we have to study the effect of external force on solids. Some solids may change their shape or size.

Complete step by step solution:
A solid has a definite shape and size. A force is always required to change its shape and size. Few materials regain their shape and size after the removal of external force, and few will not regain. Depending upon this property it is classified as elastic materials and plastic material. This property of solid materials is called elasticity and plasticity.

Elasticity	Plasticity
1) Elasticity is the property of solid material that it gains its original shape and size after the removal of applied force.	1)Plasticity is the property of solid material that it does not gain its original shape and size after the removal of applied force.
2) If we apply a small amount of force also it undergoes elastic deformation.	2) A small amount of force is not sufficient to undergo plastic deformation. It requires more force to cause plastic deformation.
3) When the solid material is elastically deformed all the other properties such as mechanical property does not change.	3) Many properties of the solid material change by a small amount for plastic deformation.
4) If you stretch a rubber band it regains its original shape and size after the removal of external force.	4) A solid piece of metal being bent its new shape shows plasticity as there is permanent change in shape and size.

Note: The elastic behaviour of materials plays an especially important role in engineering design. For example, while designing a building, bridge, automobiles etc the knowledge of elastic properties of materials like steel, concrete etc is very essential.