Deformation
When a A push or a pull. The unit of force is the newton (N). acts on an object, the object may change shape by bending, stretching or compressing - or a combination of all three shape changes. However, to change the shape of a stationary object there must be more than one force acting to do the following.
Bend an object's ends, eg diver about to jump off a diving board.
Pull an object's ends apart, eg when a rubber band is stretched.
Push an object's ends together, eg when an empty drinks can is squashed.
A change in shape is called Changing shape and/or size as a result of forces being applied.:
- Elastic materials return to their original shape and size after being stretched or squashed. deformation is reversed when the force is removed
- Inelastic materials do not return to their original shape and size after being stretched or squashed. deformation is not fully reversed when the force is removed - there is a permanent change in shape
A rubber band undergoes elastic deformation when stretched a little. A metal drinks can undergoes inelastic deformation when it is squashed.
When a material is stretched or compressed the separation between the particles is changed. In elastic deformation, the spacing will return to its original state once the force is removed. In inelastic deformation, the spacing between particles will remain changed once the force is removed.