Problem $8\mathrm{.}13$

The brake is to be designed to be self locking, that is$,$ it will not rotate when no load $\backslash (\backslash$mathbf$\{$P$\}\backslash )$ is applied to it when the disk is subjected to a clockwise couple moment $\backslash (\backslash$mathbf$\{$M$\}\_\{0\}\backslash )$ as shown in $($Figure $1).$

Figure

Part A

Determine the distance $\backslash ($ d $\backslash )$ of the lever that will allow this to happen. The coefficient of static friction at $\backslash ($ B $\backslash )$ is $\backslash (\backslash$mu$\_\{$s$\}=0\mathrm{.}35\backslash ).$ Express your answer in feet to three significant figures.

$\backslash [$

d$=\backslash$quad $\backslash$mathrm$\{$ft$\}$

$\backslash ]$