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 past each other - eg when an archer pulls an arrow back against a bow.
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. distortion is reversed when the force is removed
- Inelastic materials do not return to their original shape and size after being stretched or squashed. distortion is not fully reversed when the force is removed - there is a permanent change in shape
A rubber band undergoes elastic distortion when stretched a little. A metal drinks can undergoes inelastic distortion when it is squashed.
Learn more on forces and elasticity in this podcast
Listen to the full series on 大象传媒 Sounds.