Question

When a load of 20 kg is hung from a wire is cross-sectional area 1 sq mm, it's elongated length is 600.5 cm. If the load is withdrawn the wire shrinks by 0.5 cm in length. Calculate the youngs modulus of the wire?

Answer 1

Stress /strain = youngs modulus

stress=force /area
=20×g/(10^-6)
=2×10^8
(area is in m^2)
strain=change in length/original length
strain=0.5/600
=8.33×10^-4

youngs modulus=stress/strain
=(2×10^8)/(8.33×10^-4)
=2.4×10^11 N/m^2