i want a economies best book*Elasticity: It is a property of a body, by virtue of wich it regains its shape. and Deformation caused is known as elastic deformation
*Plasticity: Tndency of a body to retain it's shape is known as plasticity. and these kinds of substances are known as plastic substances
*When a solid deforms, atoms and molecules get displaces from equillibrium position and change in inter atomic distances. And when the force is removed they tends to come back in their mean positions.This is generally temerd as Elastic Nature of solids.
*Stress: When a body is deforming, Due to the force a opposite force develops in the body. And This Restoring force per unit area is known as Stress.
i.e Stress=Force/area
SI unit: Nm-2
Dimensional Formula: ML-1T-2
- Stress associated with decrease or increase in area is known as longitudnal stress.
- Shear stress occours when force is given tangential to the body.
- Strss associated with chang ein volume is known as hydraulic stress.
*Hooke's Law: Stress and strain take different forms and for small deformation, the stress and strain are propotional to each other and it remains same in almost all objects.
*A stress strain curve shows the relation between stress and strain.
*The elastic lmit or the maxium strain upto whic a object does not deforms is known as yeild point and corresponding stress is known as yeild strenght.
*plastic deformation is the point in wich even after removig load, the object does not retains its orgnal shape.
*Substance that can be strecth to a large limit is known as elastonomours.
* The ratio of stess strain is called modulos of elasticity.
*YOUNGS MODULOUS:
It is defined as the ratio of tensile stress to longitudnal strain. Represented a Y
i.e. Y= ( F X L) /(A X dL)
*SHEAR MODULUS:
It the ratio of corresponding shear stress to shear strain and is reresnted by G. Itis also called modulous of Rigidity.
i.e G=(F X L) / (A X dx)
and for most materials G=Y/3.
*BULK MODULUS:
The ratio of hydraulic stress to the corresponding strain is known as Bulk modulous. represented buy B.
i.e. B= -p/(dV / V)
