Springs

• Outline the basic steps of the practical

  1. Hang a spring from a clamp standing alongside a metre rule, measure the spring’s initial length.
  2. Add 10N weights and record the extension.
  3. Plot a graph of extension against force.
• Outline a caution

  A G-Clamp, so that the clamp doesn’t tip over whilst adding masses, the clamp produces a moment which counteracts the moment caused by the masses so the stand remains in equilibrium.
• What can you add to the spring to ensure that the extension measurements are accurate?

  A pointer (e.g. a splint) attached horizontally to the base of the spring and extending to the metre rule. This will make reading the length easier.
• Where should you take your ruler readings from?

  Eye level to ensure the greatest accuracy.
• What piece of safety equipment should be used throughout this experiment and why?

  Safety glasses should be worn in case of the spring breaking.
• What graph should you plot with your results?

  Extension against force (weight), you would expect it to be a straight line passing through the origin as the variables should directly proportional.
• What type of energy is stored in the spring as it is stretched?

  Elastic Potential Energy
• What can be used to calculate the elastic potential stored in the spring?

  Elastic Potential Energy = 0.5 x Spring Constant x (Extension)^2
• How does elastic potential energy relate to the graph you have drawn?

  The area under the force/extension graph.
• How can you use your apparatus and graph to work out the weight of an unknown object?

  1. Hang the object on the spring and record the extension it produces.
  2. Draw a line from that extension on your graph until it meets your plotted line and then read off the corresponding weight.