Two blocks A and $B$ shown in have a weight of $11lb$

and $6lb,$ respectively. They are resting on the incline for which the coefficients of static friction are ${}_A=0\mathrm{.}17$ and ${}_B=0\mathrm{.}23.$ Determine the angle $$ which will cause motion of one of the blocks. What is the friction force under each of the blocks when this occurs? The spring has a stiffness of $k=2l\frac{b}{f}t$ and is originally unstretched.

Part A

Determine the smallest angle $$ which will cause motion of one of the blocks.

Express your answer in degrees to three significant figures.