A-level Physics/Forces and Motion/Deformation of solids

From Wikibooks, open books for an open world
< A-level Physics‎ | Forces and Motion
Jump to navigation Jump to search

Hooke's law[edit]

This applies to an object's deformation only before the elastic limit; from then on it deforms plastically and no longer follows this law. it states that, extension is directly proportional to the applied force.

Spring Constant[edit]

The gradient refers to the gradient of a Tension-Extension graph.
The standard units of k are N m−1

Strain[edit]

Because this is a division of two measurements of length, Strain has no units and remains a ratio.

It can also be represented as

Stress[edit]

The units for Stress are N m−2, otherwise known as Pascals (Pa)

The Young's modulus[edit]

Strain energy[edit]

However, due to Hooke's Law, it can be calculated in another form, y=mx+c;

Elastic limit[edit]

the maximum extent to which a solid may be stretched without permanent alteration of size or shape.

Plastic limit[edit]

When the stress is sufficient to permanently deform the metal, it is called plastic deformation.