A cylindrical steel bar is required to support a load of 650 N. the required bar must be 0.17 m in length and must not deform by more than 0.015 mm. given that the Young's modulus of steel is 210 GPa, calculate the minumum diameter of the bar.
σ=Eε
σ=F/A=4F/πd²
ε= ΔL/L
4F/πd²=ΔL/L
d=sqrt{4FL/πEΔL} =
=sqrt{4•650•0.17/π•210•10⁹•0.015•10⁻³}=
=6.68•10⁻³ m