The keyword includes for a reason. Engineering students are mobile. They study in libraries, cafes, and dorm rooms. A physical solution manual weighs several pounds and costs significant money. The PDF version allows:

: Density, viscosity, and surface tension.

: Application to engineering devices like pumps, turbines, and nozzles. Alternative Solved Problem Resources

To give you a taste, here are two classic problem types whose solutions are detailed in the manual: