Hooke's Law

• What does Hooke's Law describe?

  Relationship between force and extension in materials

  
• What happens when a force is applied to a spring or wire?

  It stretches
• What types of materials exhibit elasticity?

  Wires and bungee ropes
• What is the condition for a material to obey Hooke's Law?

  Extension is proportional to applied force

  
• What is the Hooke's Law equation?

  F = kΔL
• What does F represent in Hooke's Law?

  Force in Newtons (N)
• What does k represent in Hooke's Law?

  Spring constant in N/m

  
• What does ΔL represent in Hooke's Law?

  Extension in meters (m)
• What does the spring constant measure?

  Stiffness of a material
• How does the spring constant relate to material stiffness?

  Larger spring constant means stiffer material

  
• What does Hooke's Law apply to?

  Both extensions and compressions

  
• How is extension defined?

  Increase in length of an object
• How is compression defined?

  Decrease in length of an object
• How is extension calculated?

  Extension = stretched length - unstretched length
• What does stretching a spring with a load produce?

  A force that leads to extension

  
• What does a force-extension graph show?

  Material's response to a given force

  
• What indicates a material obeys Hooke's Law on a graph?

  A straight line through the origin
• What happens to the graph as more force is added?

  The graph starts to curve slightly
• What is the Hooke's Law region on a graph?

  Linear portion where Hooke's Law is obeyed
• What is the limit of proportionality?

  Point beyond which Hooke's Law fails

  
• What happens beyond the elastic limit?

  Material won't return to original length
• What does the gradient of a force-extension graph represent?

  Spring constant

  
• What is the relationship between the gradient of an extension-force graph and spring constant?

  Gradient equals $\frac{1}{k}$

  
• What should you check before finding the spring constant?

  Check the axes of the graph

  
• What happens if force and extension axes are swapped?

  Gradient is $\frac{1}{k}$