Saturday, October 24, 2015

1.29 Describe experiments to investigate how extension varies with applied force for helical springs, metal wires and rubber bands

When a force is applied to a wire, rubber band or spring, they extend (and usually spring back into shape). To investigate how the force applied affects extension, you could conduct the following experiment, or something similar:

  1. Attach a spring to a newton meter. Measure the length of the spring.
  2. Attach a 10g mass and measure the spring length again.
  3. Keep increasing the mass attached to the spring by 10g until you reach a given amount (for this example, let's say 80g) and measuring the new spring length.
  4. Calculate the extension (how long the spring stretched by subtracting the original length from the new length)
  5. Plot a graph
When you plot the graph, you should see that the extension increases with the force applied (which would've been shown by the newton meter)

Note that when the graph curves, the elastic limit of the object (in this case, the spring) has been reached.


4 comments:

  1. Hi, thanks for this amazing blog, but if we are calculating the extension, don't we need to subtract the final length from the original length?

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    Replies
    1. As the original length is shorter than the final length, we have to subtract original from final.

      For example, if a spring is 5cm long without extension, and 10cm with mass added to it, we have to do 10-5 to find the length it has been extended by.

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  2. https://www.youtube.com/watch?v=2ft954vXPa4

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