Practice Problem:

Hint: $=0\mathrm{.}005"$ as that's the max elongation, $L=24",$ Modulus of Elasticity $(E)=29,000,000$

A $24-$inch$-$long round steel bar resists a tensile force of $10,000$ pounds.

$($a$)$ What is the required diameter if its unit stress may not exceed $24,000$ psi?

$($b$)$ What is the required diameter if its elongation is not to exceed $0\mathrm{.}005"?$

Solution:

$($a$)$

$f=24,000$

$P=10,000$#

$A=\frac{d^2}{4}$

$f=\frac{P}{A}$

$24,000=\frac{10,000\text{\#}}{\frac{d^2}{4}}$

$d^2=$

$d=$

$($b$)A=P\frac{L}{}E=$