A solid shaft produced from the $1045$ steel in the figure must be $240cm$ long and must survive continuous operation for $1\mathrm{.}5$ YEAR with an applied load of $6000N.$ The shaft makes one revolution per minute during operation. What must be the diameter of the shaft that will satisfy these requirements?

What must be the diameter if the shaft would work without fracture indefinitely?

The maximum stress acting on this type of shaft is $=10\mathrm{.}18$

$L^{**}\frac{F}{d^3}$

$L$ is the length of the bar and $F$ is the load and $d$ is the diameter.