일반물리학 1 — Force and Motion-II: Problem 25

25 Block $B$ in Fig. 6-31 weighs 750 N. The coefficient of static friction between block and table is 0.25; angle $\theta$ is $30^\circ$; assume that the cord between $B$ and the knot is horizontal. Find the maximum weight of block $A$ for which the system will be stationary.