$3.(40$ pts $)$ Mass A is connected by a weightless rope mass $74$ kg $.$ While mass A is accelerating downwar wit suddenly acted upon by a moment $\backslash ($ M$=66\backslash$mathrm$\{$~N$\}\backslash$cdot $\backslash$mathrm$\{$~m$\}\backslash )$ cou ercl Determine the mass of A $,$ and the components of theact

$8$ over a smooth drum to a disk $\backslash ($ B $\backslash )$ of h an acceleration $\backslash (1\mathrm{.}5\backslash$mathrm$\{$~m$\}/\backslash$mathrm$\{$s$\}^\{2\}\backslash ),$ the disk is pckwise as shown in the figure. fon at $\backslash ($ O $\backslash )$ on disk $\backslash ($ B $\backslash )$ at this instant.