Hooke’s Law

• What is needed to squash or stretch a stationary object?

  Two forces that push or pull
• How does applying one force affect an object?

  It changes the motion of the object
• What must you do to squash an object?

  Apply a force from either side
• What is required to stretch a spring?

  Two forces pulling either end of the spring
• What happens when you apply a force to a spring?

  It creates a tension force upwards
• What do elastic objects do after being stretched?

  Return to their original shape
• What is the difference between elastic and inelastic objects?

  Inelastic objects do not return to original shape
• What does Hooke's law state?

  Double the force, double the extension
• How can you investigate Hooke's law with a spring?

  Measure extension with varying weights
• What is the weight of a 10-gram mass?

  0.1 Newtons
• How do you calculate the extension of a spring?

  Subtract original length from new length
• What is the independent variable in the spring experiment?

  The force applied to the spring
• What is the dependent variable in the spring experiment?

  The extension of the spring
• What is a control variable in the spring experiment?

  The type of spring used
• What does a graph of force against extension show if Hooke's law is obeyed?

  A straight line through zero
• What happens to the graph if the object is overstretched?

  The graph curves off and loses elasticity
• What is the elastic limit of a spring?

  The point beyond which it loses elasticity
• What are the characteristics of elastic and inelastic objects?

  • Elastic objects:
  • Return to original shape after stretching
  • Example: Springs
  • Inelastic objects:
  • Do not return to original shape
  • Example: Blu-tac
• What are the key variables in the spring experiment?

  • Independent variable: Force applied (weight)
  • Dependent variable: Extension of the spring
  • Control variable: Type of spring used
• What does Hooke's law describe about force and extension?

  • States that extension is proportional to force
  • Doubling the force doubles the extension
• What happens when a force is applied to an object?

  It can change its size and shape
• What does this law describe?

  The relationship between force and spring extension