I started reading a great textbook and thought I would share some of its finer points. It is a great introduction to mechanics of solids and liquids, although the title explicitly states Earth and Environmental Sciences. Gerard V. Middleton (Prof. Emeritus, McMaster Univ) and Peter R. Wilcock (Johns Hopkins), "Mechanics in the Earth and Environmental Science," Cambridge University Press, 1994. 1. Introduction 2. Review of elementary mechanics 3. Dimensional analysis and theory of models 4. Stress 5. Pressure, buoyancy and consolidation 6. Flow through porous media 7. Strain 8. Elasticity 9. Viscous fluids 10. Flow of natural materials 11. Turbulence 12. Thermal convection Appendices References This is the case for a central body force (gravity). In reality, variations in density (e.g. granite or basalt compared to water) or elevation (mountains) cause perturbations in the gravitational force field. For many other problems concerned with solid bodies, one must be concerned with the size and shape of the material, as well as its mass. For example, a boulder moved by water or a round object rolling down an incline. This is an important point to keep in mind, particularly at the beginning of model development. The issue of element size is more complicated when significant thermal gradients are present since properties like density and strength, or solubility of different phases may be significantly affected by temperature (internal energy). When a radiation field is imposed on a material, the modeling can be even more complex. There are relevant topics in the other tutorials in this section and the physics tutorials sections, as well as the forums Mechanical & Aerospace Engineering and Materials & Chemical Engineering Some definitions: Statics - study of equilibrium of forces, i.e. there is no acceleration because the net forces and net moments are null. Kinematics - study of motion, exclusive of masses and forces. Dynamics - study of the relationship of motion and forces All three are included within mechanics.