Q$3.($Bonus$)$ A $6-$kg block $B$ rests as shown on a $10-kg$ bracket $A.$ The coefficients of friction are ${}_s=0\mathrm{.}30$ and ${}_k=0\mathrm{.}25$ between block $B$ and bracket $A,$ and there is no friction in the pulley or between the bracket and the horizontal surface. Determine $i)$ the maximum force $P$ which may be exerted on the cord if block $B$ is not to slide on bracket $A,ii$ the corresponding acceleration of the bracket, $A.$