i$)$ Determine the force $\backslash ($ F $\backslash )$ required on the brake lever in $($a$)$ below, for $200$ Nm braking torque, drum rotation as shown in the picture.

ii$)$ Prove that the brake shown in $($b$)$ will not be self$-$supporting for the direction of rotation shown.

iii$)$ If the force F on the lever in $($b$)$ is $400$ N $,$ what will the brake torque be$?$

$[8]$