Question

A copper wire and an aluminium wire have length's in the ratio 3:2.diameters n the ratio 2:3 AND FORCES APPLIED IN THE RATIO 4:5 find the ratio of increase in length of the two wires.(Y FOR COPPER =1.1*1O^11
N/m^2,Y for aluminum=0.70*10^11 N/m^2).
ans:
1)189:110

Answer 1

X = Length increase = L*Force/(Area)(Y)

Y is Young's modulus

X(copper)/X(aluminum) = (3/2)*(4/5)/[(2/3)^2*(1.1/.7]
= 1.718
which happens to equal 189/110