Energy stored in elastic materials

—> when a material is extended or compressed by a force, it will store energy until the force is applied and it returns to its original shape.

—> if a material returns to its original shape after a force is removed this is known as elastic deformation.
—> if a material is permanently deformed after a force is removed this is knowing as plastic deformation.

—> if plastic deformation occurs, the material had gone beyond its elastic limit.

—> to stretch the spring, you are using energy which is transferred into stored energy in the spring.
—> if ever a transfer of energy takes place, we say that work is done.

—> in the case of our stretched spring, the energy stored (work done on the spring) is the area of the graph of F against x.

Spring constant : force required to spread a material by 1m.

Show that energy stored in a spring can be calculated using the following formulas :

• △ E = 1/2 F △x
• △ E = 1/2 k (△x)^2