L21 : Kinetics of a Particle

There are four approaches to the solution of kinetics problems.

(A) Direct application of Newton's second law.

(B) D'Alembert's principle

(C) Use of work and energy

(D) Solutions by impulse and mometum methods.

Newton's Second Law :

The acceleration of a particle is proportional to resultant force acting on it and is in the direction of this force.

F = ma

where F is the resultant force and a is the acceleration.

This relation can be verified only experimentally.

Assume the existance of a fixed primary inertial system. Newton's second law is valid in this system as well as with respect to any nonrotating reference system that translates with respect to the primary system with a constant velocity. Such a system is called an inertial system.