Two crates of mass are stacked on the back of a truck (Fig. P4.54). The frictional force...

Two crates of mass are stacked on the back of a truck (Fig. P4.54). The frictional forces are strong enough that the crates do not slide off the truck. Assume the truck is accelerating with Draw free-body diagrams for both crates and find the values of all forces in your diagrams.