SOLUTION: The resistance of a wire to the transmission of electricity varies directly as the length of the wire and inversely as the square of the radius of a cross section of the wire. An 8

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Question 451569: The resistance of a wire to the transmission of electricity varies directly as the length of the wire and inversely as the square of the radius of a cross section of the wire. An 800m has a radius of 0.48cm and ha a resistance of 0.3125 ohms. if another wire made from the ame metal has a length of 500 m and a resistance of 0.5 ohms, what is the radius?
Answer by stanbon(75887) About Me  (Show Source):
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The resistance of a wire to the transmission of electricity varies directly as the length of the wire and inversely as the square of the radius of a cross section of the wire.
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r = kL/r^2
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Solve for "k" using "An 800m has a radius of 0.48cm and ha a resistance of 0.3125 ohms".
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0.3125 = k*800/(0.48)^2
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k = 0.00009
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Equation:
r = 0.00009L/r^2
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If another wire made from the same metal has a length of 500 m and a resistance of 0.5 ohms, what is the radius?
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r = 0.00009*500/(0.5)^2
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r = 0.18 ohms
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Cheers,
Stan H.