Chapter 6.3, Problem 2P

The 50-kg block rests on the horizontal surface, and a force $\text{P= 200 N,}$ whose direction can be varied, is applied to the block. (a) If the block begins to slip when $\theta$ is reduced to 30°, calculate the coefficient of static friction ${\mu }_8$ between the block and the surface. (b) If P is applied with $\theta =45°,$ calculate the friction force F.