Forces and elasticity

• Elastic deformation


  Changes in an object's length or shape that are reversible when the forces are removed
• Inelastic deformation


  Changes in an object's length or shape that are not reversible when the forces are removed
• Applying forces to an elastic material

  1. Stretching forces are equal in magnitude but opposite in direction

  2. Squeezing forces cause compression

  3. Applying three forces causes bending
• Elastic materials return to their original length or shape when forces are removed
• To change an object's length or shape, more than one force must be applied
• Force to stretch an elastic object

  Force (N) = Spring constant (N/m) x Extension (m)
• Compression


  The distance an elastic object is squeezed, represented by 'e' in the force equation
• Elastic potential energy


  Energy stored in an elastic object when it is stretched or compressed
• The work done equals the elastic potential energy, if the object is not inelastically deformed