What is elastcity

Elasticity

Elasticity is the ability of a deformed material body to return to its original shape and size when the forces causing the deformation are removed. An object which can do this behaves elastically.   The force possessed by an elastic object when it is stretched or compressed is known as elastic force.   Objects which do not return to their original size when stretched are called inelastic.  

Examples of elasticity

When a rubber band is stretched, a force is felt that feels like the band is resisting a change or deformation to its shape. This force is called the elastic force and the force is lost as soon as the external force is removed.

Figure 1:  An elastic band will change shape when it is pulled apart.  Once it is no longer being pulled apart, it will return to its normal shape.

Springs are one of the best examples of elastic force because they return to their original shape after undergoing deformations such as compression and expansion. 

Figure 2: A spring when stretched will compress and return to its normal shape.

Figure 3:  When you pull on the rubber sling of a catapult, the rubber stretches.  When you release the rubber, the rubber will compress back to its normal size.

A bow and arrow would not work without elastic force. The archer pulls the string attached to the ends of the bow towards his/her side. The string being elastic resists the change in shape and gets back to its original place as soon as the archer releases it. This helps the arrow to move forward and hit the aim.