Chapter 5, Problem 56P

GO In Fig. 5-51a, a constant horizontal force ${\stackrel{\to }{F}}_a$ is applied to block A, which pushes against block B with a 20.0 N force directed horizontally to the right. In Fig. 5-51b, the same force ${\stackrel{\to }{F}}_a$ is applied to block B; now block A pushes on block B with a 10.0 N force directed horizontally to the left. The blocks have a combined mass of 12.0 kg. What are the magnitudes of (a) their acceleration in Fig. 5-51a and (b) force ${\stackrel{\to }{F}}_a$?

Figure 5.51 Problem 56.