Chapter 6, Problem 5P

GO A 2.5 kg block is initially at rest on a horizontal surface. A horizontal force $\stackrel{\to }{F}$ of magnitude 6.0 N and a vertical force $\stackrel{\to }{P}$ are then applied to the block (Fig. 6-17). The coefficients of friction for the block and surface are µ_s = 0.40 and µ_k = 0.25. Determine the magnitude of the frictional force acting on the block if the magnitude of $\stackrel{\to }{P}$ is (a) 8.0 N, (b) 10 N, and (c) 12 N.

Figure 6-17 Problem 5.