**Elasticity:**

When exerting a force on an isotropic material , the deformation of its dimensions is proportional to the exerted force .

There are Two Types of deformations:

1.

**Elastic**: the material gains back its original shape

2.

**Plastic**: the deformation is permanent.

T=F/A

Hooke's Law: A Law stating that, in a linear system, the restoring force is proportional to the displacement of the body, acting in a direction as to restore equilibrium.

Where

F = restoring force [N]

k = spring constant [Nm-1]

x = elongation of material [m]

**Hook’s law:**

The exerted force on a body is directly proportional with the change in its length.

F=kΔX E=KLo/A

Generalized hook’s law:

εx=Tx/E-σTy/E-σTz/E

εy=1/E [Ty-σ(Tx+Tz)]

εz=1/E [Tz-σ(Ty+Tz)]

For More Information See also :

## This Document is from Mit Physics department and its free to view ,

Author : H.Frank Morrison

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