Q1 A steel wire of length 4.7 m and cross-sectional area stretches by the same amount as a copper wire of length 3.5 m and cross-sectional area of under a given load. What is the ratio of the Young’s modulus of steel to that of copper?
Let the Young's Modulus of steel and copper be YS and YC respectively.
Length of the steel wire lS = 4.7 m
Length of the copper wire lC = 4.7 m
The cross-sectional area of the steel wire AS =
The cross-sectional area of the Copper wire AC =
Let the load and the change in the length be F and respectively
Since F and is the same for both wires we have
The ratio of Young’s modulus of steel to that of copper is 1.79.