Question

A copper wire of length 2.2 m and a steel wire of length 1.6 m, both of diameter 3.0 mm, are connected end to end. When stretched by a load. the net elongation is found to be 0.70 min. Obtain the load applied
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Answer 1

Given that,

Length of the copper wirel 1

=2.2m

Length of the steel wire l2=1.6m

Elongation in length△l=0.5.mm

=0.5×10−3 m Radius of theCu wire r1

=1.5×10 −3 mY 1

=1.1×10 11 N/m 2Y 2

=2.0×10 11N/m 2

Let F be the stretching force in both the wires then, for Cu wire, Y 1= πr 12F× l1l1

⇒F= l 1Y 1πr 12×l1= 2.21.1×10 −11x 722×(1.5×10−3) 2×0.5×10 3=1.8×102

N So the streching force in the copper wire be 1.8×10 2N

Hence, the answer is 1.8 X 10²N