Newton’s Laws of Motion

Newton's laws of motion are of fundamental importance in classical physics. Newton gave three laws connected with motion and are, popularly, known as Newton’s laws of motion.

(a) First Law (Law of Inertia)

Everybody continues in its state of rest or of uniform motion in a straight line unless it is compelled by some external force to change that state

(b)Newton's Second Law

The rate of change of momentum of a body is directly proportional to the impressed force and takes place in the direction of the force.

     So, F= dp/dt

     This results force acting a body F is equal to the mass of the body m times acceleration of the body a.

     So, F = ma

(c)Newton's Third Law

'Action - Reaction' Pair when a Man Jumping From a Boat

To Every action there is an equal and opposite reaction.

FAB = - FBA 

The first two laws relate to the type of motion of a system that results from a given set of forces. The third law studies the basic nature of all forces i.e. they act in action - reaction pair.

"Newton's laws of Motion" is one of the easiest and important chapters of Mechanics in the Physics syllabus of IIT JEE, AIEEE and other engineering examinations. These laws are not new to any aspirant as he is using these laws even in previous classes. The examples based on this are very easy and can be seen even in day to day life.

The chapter is important not only because it fetches 2-3 questions in most of the engineering examination but also because it is prerequisite to the other chapters of Mechanics.