Mechanics can be defined as the science which describes and predicts the conditions of rest (statics) or motion (dynamics) of bodies under the action of forces. In reality, things are never absolutely rigid and deform slightly when acted upon by a force. These deformations are minute and do not effect the equilibrium of the structure. Deformations are important considerations with respect to the resistance of the structure to failure. Mechanics is the foundation of most engineering sciences. The purpose of mechanics is to explain and predict physical phenomena and thus to lay the foundations for engineering applications. Sir isaac newton (late 17th century) first formulated fundamental principles of mechanics. These principles were later modified by d"alembert, lagrange, and hamilton. The study of mechanics actually goes back to the days of aristotle (4th century b. c. and archimedes (3rd century b. c. ) These concepts cannot be truly defined, but they should be accepted on the basis of our intuition and experience.