R. Practical- Forces & Extension

• Spring Constant= Force × Extension
• How can the extension of a spring when a weight is added be determined?

  • Measure start and end length
  • Subtract start length away from length when weight has been added
• What do you use to measure extension of spring?

  Ruler
• How will the appearance of a spring change when a weight is added?

  Spring will become longer, thinner and gaps between each coil will increase
• How could you determine the limit of proportionality for a spring?

  • Add weights and measure extension
  • Plot extension against force and look for where line is no longer showing a linear relationship
• What is the relationship between force and extension of a spring provided the limit of proportionality has not been exceeded?

  Directly proportional
• How could you increase accuracy of limit of proportionality that you could determine in this experiment?

  Use smaller intervals
• What form of energy is stored in a stretched spring?

  Elastic
• How could you identify on a graph where the limit of proportionality has been exceeded?

  When line starts to curve, so relationship is no longer directly proportional
• What improvements could be made to investigation to ensure the length of the spring measured is accurate?

  Make sure spring is stationary before measuring length and use a pointed on end of spring to measure length
• How could you test after adding weights if spring is still behaving elastically?

  Remove weights and see if it returns to original shape
• Risks

  1. Weights falling on feet
  2. Clamp stand falling off desk
• Safety Precautions

  1. Secure clamp stand on desk using G-clamp
  2. Place a tray of sand on floor under test spring
• 1. Set up equipment as shown in the diagram.
  2. Adjust the ruler so that the zero mark is at the same height as the top of the spring.
  3. Record the length of the spring when no weights are attached.
  4. Hook a 1N weight on the bottom of the spring.
  5. Record the new length of the spring.
  6. Add weights at 1N intervals recording the new length of the spring.