Question

A 10-m-long copper wire is pulled with a force of 1300 N and it stretches 10 cm. Calculate the radius of the copper if the value of the Young's modulus is

110 ✕ 10⁹ N/m².

Assume the cross section of the wire is circular.

Answer 1

We know that young modulus

Y=FL/A∆L

A=FL/Y∆L ..1

here F=1300N , L=10 m , ∆L=10cm=0.10m. Y=110×10⁹ N/m²

put these value in equation 1

A=1300×10/(110×10⁹×0.10)

A=1.182×10^-6

since cross section of the wire is circular

πr²=1.182×10^-6

r²=0.3762×10

r=0.613×10^-3 m

r=0.613 mm .