Two blocks A $($mA $=5\mathrm{.}1$ kg$)$ and B $($mB $=2\mathrm{.}1$ kg$)$ are each pin$-$connected to a rigid rod of negligible mass $(=0\mathrm{.}5$ m$).$ The system is released from rest in the position depicted in the vertical plane, where $=7\mathrm{.}5,$ $=61\mathrm{.}3$ and B$\text{'}$s slot is vertical. Assume the slots in which the blocks slide are smooth and each block contacts only one side of its slot at any instant.

Find the magnitude of the acceleration of block A and the magnitude of the acceleration of block B at the instant the system is released from rest.

Find the magnitude of the force of the arm on the particle at this instant.

Find the smallest coefficient of static friction s that will permit the box to avoid slipping on the vehicle if the ramp angle $($see figure$)$ is $=13\mathrm{.}5.$