Question 190317
The stretch on a wire under a given tension varies directly as the length of the wire and inversely as the square of its diameter.
stretch = k[L/d^2]
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 A wire having length 2m and diameter 1.5mm stretches 1.2 mm.
1.2 = k[2/1.5^2]
1.2 = k[8/9]
k = (9/8)1.2
k = 27/20
So the equation for your problem is stretch = (27/20)[L/d^2]
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 If a second wire of the same material(and under the same tension) has length 3m and diameter 2.0mm, find the amount of stretch. 
stretch = (27/20)[3/2^2] = 1.0125
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Cheers,
Stan H.
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