Memory Anchor:

• Super Challenge:

  Stretch:

  Challenge:

Key Questions:

1. What causes a spring to deform?
   • A spring will deform (stretch or compression) until the tension balances the load placed upon it.
2. What happens to an object when it is deformed elastically?
   • When a spring (or any object) is deformed elastically it will go back to its original shape.
3. What energy transfers occur when an object is deformed elastically?
   • When a spring (or any object) is deformed elastically, there is work done as kinetic Energy is transformed into elastic (strain) potential Energy.
4. What happens to the elastic potential energy of a spring as it returns to its original shape?
   • The elastic (strain) potential Energy can be retrieved as the object returns to it shape, normally in the form of kinetic Energy.
5. What happens to an object when it is deformed plastically?
   • Force-extension linear relation; Hooke's Law as a special case
6. What energy transfers occur when an object is plastically deformed and where is the energy?
   • When a spring (or any object) is deformed plastically kinetic Energy is used to overcome the Forces between Particles. This Energy ends up as thermal Energy as the Particles are vibrating more.
7. What is happening to a spring during the linear region of a force-extension graph? At what point does the spring stop obeying Hooke's law?
   • While in the linear region of a Force-extension graph, the spring is obeying Hooke's Law and the deformation is elastic. Past the limit of proportionality, the spring does not obey Hooke's Law and is being plastically deformed.