Hi there! Can anyone help me with a problem.(adsbygoogle = window.adsbygoogle || []).push({});

I did an experiment at school trying to measure the Young's modulus of a copper wire. We attached one end of the copper wire to a clamp and then tied on weights of 100g at a time to the other end so that a force can be applied to the copper wire and so it stretches.

To work out Young's modulus, we require two things: the stress and the strain of the wire.

Stress is [tex]\sigma = \frac{F}{A}[/tex] and strain is [tex]\varepsilon = \frac {\delta \ell}{\ell_o}[/tex] [tex]\frac {change in length}{original length}[/tex].

To work out Stress, I worked out the Force applied on the wire by the weights (using the equation Force = Mass [tex]\times[/tex] Gravitational potential energy) as 0.1kg [tex]\times[/tex] 10 and this in turn produces 1N of force everytime a weight is added. To work out the area of the copper wire, I measured the diameter using a micrometer and this gave me an measurement of d=0.35mm. From this I worked out the cross section of the wire:

[tex]\frac{0.35}{2}[/tex] (to find the radius), then squaring this and multiplying by [tex]\pi[/tex] to obtain the area.

For stress I measured the original length of the wire (337cm) and then measured the extension of the wire and then dividing this by the original length.

My results table is attached.

When I try and plot the graph, I end up with a curved graph so the Young's modulus is not a straight line and so is the not directly proportional. Can anyone help me and tell me what I have done wrong in my experiment or is a curved line correct? Are my results alright?

Thanks

:shy:

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# Homework Help: Young's modulus of a copper wire

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