Elasticity

• Explain the relationship between the force applied and the extension of an elastic object


  The extension is directly proportional to the force applied, provided that the limit of proportionality is not exceeded
• What is meant by inelastic deformation?


  The deformation which results in the object being permanently deformed/stretched, the object doesn't return to its original shape when the force is removed.
• State the equation linking force, spring constant and extension


  FORCE = SPRING CONSTANT X EXTENSION

  (N) (N/M) (M)
• What type of energy is stored in a spring when it is stretched?

  Elastic potential energy
• Which law is related to elastic objects and extension?


  Hookes Law - stating that the extenstion of an elastic object (ie spring) is directly proportional to the force applied - provided its limit of proportionality is not exceeded!
• Which formula links to Hookes law?


  F = KX

  -F is the force applied to the spring (N)

  -K is the spring constant (Nm-1)

  -X is the extension (M!!)
• What does a linear line mean on a force/extension graph?

  -The linear gradient is an elastic region - it is following Hookes law and therefore acting elastically

  -The gradient is K(spring extension) in the formula (F=KX)
• How is the limit of proportionality shown on a linear force/extension graph?


  Through a non-linear line (shallow line)- meaning the object is now following plastic behaviour - it is NOT following Hookes law
• What does it mean is a force/extension graph has JUST a linear section?

  This means the object is brittle and so it snaps instead of stretching after reaching its elastic limit
• How many forces must be applied to an object in order to bend/compress it?


  More than one - if only one force is applied the object will simply move in that direction instead of compressing or bending!