<li>A certain copper wire has a resistance of 10.0 ohms. At what point along the length must the wire be cut so that the resistance of one piece is 7.0 times the resistance of the other? Caclculate the resistance of each piece.</li>
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<p>I started out with a diagram of my own and wrote some relationships. But I don’t know what to do from there.</p>
<p>R=rho L/A; L = y+x, Ry=7Rx</p>
<p>and y is the long length, and x is the short length. Please help.</p>
<p>For the first one, resistance only depends on the physical structure of the wire. It is calculated as rho*L/A where rho(p) depends on the material.
so rho(L1)/A = 7 * rho(L2)/A and L1 + L2 = 1 m
L1/L2 = 7 and L1 + L2 = 1 plug in L2= 1- L1. I used my 89.
L1 = .875 and L2 = .125. L1 will have the greater resistance.</p>
<p>Now you know that 10 ohms = rho*1m/A and then you need to calculate it for when it is .875m and .125m.</p>
<p>Oh I understand it now. Thanks a lot.</p>