Two blocks, A and $B,$ each weigh $50$ N and are connected by a spring with stiffness $k=2lbfft.$ The coefficients of friction between blocks A and $B$ and the surface are ${}_A=0\mathrm{.}8$ and ${}_B=0\mathrm{.}3,$ respectively. The surface angle slowly increases from $=0$ until one block moves and the spring length begins to change from its initially unstretched$/$uncompressed condition. The surface angle is increased further until both blocks slide down the ramp together. From this information, determine:

a$)$ The angle ${}_{\text{I}}$ at which one block first moves and the spring length begins to change.

b$)$ The angle ${}_2$ at which both blocks slide off the ramp.

Answers:

${}_1={16\mathrm{.}6}^{-}$

${}_2=33\mathrm{.}02$