Submitted by,

Anitha.K.P

Physical Science

B N V C T E

NEWTONS’S LAWS OF

MOTION

Sir.Isaac Newton

(1642-1727)

Newton's laws of motion consist ofthree physical laws that form the basisfor classical mechanics. They describe therelationship between the forces acting on abody and its motion due to those forces.

The three laws of motion were first compiledby Sir Isaac Newton in his work ”PhilosophiæNaturalis Principia Mathematica”, firstpublished on July 5, 1687. Newton used themto explain and investigate the motion of manyphysical objects and systems

Newton's First and Second laws, in Latin, from the original 1687 edition of the Principia Mathematica.

Every body remains in a state of rest oruniform motion (constant velocity)unless it is acted upon by an externalunbalanced force.This means that in the absence of anon-zero net force, the center ofmass of a body either remains at rest,or moves at a constant speed in astraight line.

This tendency is also known as inertia

INERTIA

The ball doesn't move

unless it is acted upon by

an external unbalanced

force

Inertia is the

tendency of

an object to

resist

changes

Momentum of a body is defined as the product of its mass and velocity

P(momentum) = M(mass) x V(velocity)

Second law of motion

The rate of change of momentum of an object isproportional to the applied unbalanced force in thedirection of the force

When mass is in kilograms and accelerationis in m/s² , the unit of force is in Newton (N).One Newton is equal to the force required toaccelerate one kilogram of mass at onemeter/second square

We know that objects with different masses accelerate to the ground at the same rate.

However, because of the 2nd Law we know that they don’t hit the ground with the same force.

F = ma

98 N = 10 kg x 9.8 m/s/s

F = ma

9.8 N = 1 kg x 9.8 m/s/s

Newton’s 3rd law of motion

For every action, there is an equal and oppositereaction.This may be the most popular law in the universe !This law is sometimes referred to as the action-reaction law, with F called the "action" and −F the"reaction". The action and the reaction aresimultaneous.

According to Newton, whenever objects A and B interact with each other, they exert forces upon each other. When you sit in your chair, your body exerts a downward force on the chair and the chair exerts an upward force on your body.

•SCERT science text book of 8th class

•Wikipedia