In the block brake shown below, the brake torque applied on the drum is $85$N$.$m$.$ The design dimensioms are: a$=110$mm$,$ b$=410$mm$,$ c$=70$mm$,$ brake drum diameter$=180$mm$,$ u$=0\mathrm{.}3$

A$)$ Find Fi force Required to appliy brake when drum roates anti$-$clockwise

B$)$ Find Fi forfe required to apply brake when drum rotates clockwise.