Prof.Kodali Srinivas

Jean le Rond d’Alembert D’Alembert’s principle This principle,  is alternative form of  Newton’s second law  of motion, stated by the 18th-century French polymath Jean le Rond d’Alembert. In effect, the principle reduces a problem in dynamics to a problem in statics. The Newton's second law states that the force  F  acting on a body is equal to the product of the mass  m  and acceleration  a  of the body, or                     F  =  ma The above equation will be re write in  D’Alembert’s form is                             F  -  ma  = 0   In other words, the body is in equilibrium under the action of the real force ' F'  and the  fictitious force (  - ma) . The fictitious force is also called an ' inertial force'  and a reversed effective force. Acceleration of a Body in Curvilinear Motion Components of total acceleration in normal and tangential directions (t - n axis) The tangential acceleration , tangent to trajec

In Engineering Mechanics   the study of the causes of motion and changes in motion is called as D ynamics .  For convenience, dynamics is divided into two branches,   Kinematics and   Kinetics . Kinematics  : It is the branch of classical mechanics that describes the motion of bodies (objects) and systems (groups of objects) without consideration of the forces that cause the motion. Kinetics: It is the branch of classical mechanics that describes the motion of bodies (objects) and systems (groups of objects) by consideration of the forces that cause the motion. Types of Motion: There are three types of motion, Translatory motion Rotatory motion Vibratory motion Translatory motion: In translatory  motion the particle moves from one point in space to another. This motion may be along a straight line or along a curved path. Motion of a particle along a straight line is called Rectilinear motion and  Motion  along a curved path is called C urvilinear mot