FORCE AND LAW OF MOTION

ISAAC NEWTONSir Isaac Newton was an English physicist and mathematician who

is widely Regarded as one of the most influential scientists of all time and as a key figureIn the scientific revolution . Newton also made seminal contribution to opticsAnd shares credit with Gottfried Leibniz for the invention of the infinitesimal Calculus. He gave 3 law of motion.

FORCE A push or pull on a body is called force .Forces are used in our everyday actions like pushing ,pulling, lifting,stretching, twisting and pressing.

EFFECT OF FORCE

A force cannot be seen. A force can be judged only by the effects which it canproduce in various bodies (or objects) around us.

A force can move a stationary body . A force can stop a moving body . A force can change the speed of a moving body . A force can change the direction of a moving body . A force can change the shape (and size ) of a body .

A force ca

n move a stationary

body

A force can stop a moving body

A force

can ch

ange the sp

eed of a m

oving

body

A force

can ch

ange the dire

ction of a

movin

g

body

A force

can ch

ange the sh

ape (and siz

e )

of a body

FORCES ARE TWO TYPES Balanced Forces Unbalanced forces

BALANCED FORCESIf the resultant of all the forces acting on a body is zero,the forces are called

Balanced forces . If a number of balanced forces act on a stationary body , theBody continues to remain in its stationary position . If a number of balanced Forces act on a body in uniform motion , the body to be in its state of uniform Motion . Though balanced forces cannot produce motion in a stationary bodyOr stop a moving body , they can , however , change the shape of the body .The four forces acting on the box are :-

Force of our push Force of friction Force of gravity Force of reaction

BALANCED FORCES

UNBALANCED FORCESIf the resultant of all the forces acting on a body is not zero , the forces are calledUnbalanced forces . Unbalanced forces can move a stationary body or they can stop a moving body . To move a stationary object , we have to push it with a Force greater than the opposing force of friction . If we release the suitcase fromour hand , then the unbalanced force of gravity acts on it and the suitcase fallsto the ground .When an unbalanced force act on a body , it produces motion in the body . An unbalanced force can also stop a moving body . If there were nounbalanced force of friction and no air resistance , a moving bicycle would go onmoving for ever . The four force acting on the toy car :- Force of our push Force of friction Force of gravity Force of reaction of ground

UNBALANCED FORCES

NEWTON ‘S LAW OF MOTIONNewton has given three laws to describe the motion of bodies .

These laws are known as Newton’s laws of motion . Isaac

Newton : The scientists who gave the law of motion and law of gravitation . The Newton’s laws of motion give a precise

definition of force and establish between the force applied on a body a And the state of motion

acquired by it.

NEWTON’S FIRST LAW OF MOTION

A body at rest will remain at rest , and a body in motion will

continue in

motion in a straight line with a uniform speed , unless it is

compelled by

an external force to change its state of rest or of uniform

motion .Inertia is

that property of a body due to which it resists a change in its

state of rest or

of uniform motion . Heavier mass is a measure of the inertia of

a body . If

objects have more inertia than lighter objects .The second part

of the first

law of motion will continue to move unless a force compels it to

change its

state of uniform motion in a straight line .To overcome the

inertia and make

a body move from rest , we must apply an external force . It

should be noted

that Newton’s first law of motion is also some times called

Galileo’s law of

inertia .

NEWTON’S FIRST LAW OF MOTION

MOMENTUMThe force required to stop a moving body is directly proportional to its mass .The force required to stop a moving body is also directly proportional to itsvelocity . The quantity of motion in a body depend on the mass and velocityof the body . This gives us another term known as “momentum” . The momentum of a body is defined as the product of its product of its mass andvelocity . Momentum = mass *velocity (p = m*v). If a body is at rest , its velocity is zero and hence its momentum is also zero . Momentum is a vector quantity and takes place in the direction of velocity . The SI unit of momentum is Kilogram metres per second (Kg.m/s or Kg.ms-1 ).Every moving body possessesmomentum . Momentum is considered to be a measure of the quantity ofmotion of a moving body .

MOMENTUM

NEWTON’S SECOND LAW Of MOTIONThe rate of change of momentum of a body is directly proportional to the force

and takes place in the direction in which the force acts . Newton’s second law of motion gives us a relationship between ‘force’ and ‘acceleration’. Newton’ssecond law of motion also gives us a method of measuring the force in terms of mass and acceleration . The acceleration produced in a body is directly proportional to the force acting on it and inversely proportional to the mass of the body . If the mass of a body is doubled , its acceleration will be halved . AndIf the mass is halved then acceleration will get doubled . The SI unit of force isNewton which is denoted by N. A Newton is that force which when acting on aBody of mass 1 kg produces an acceleration of 1 m/s2 in it . Newton’s second Law of motion gives us a relationship between the force applied to a body and The acceleration produced in the body . 1 newton = 1 kg * 1 m/s2 Force = mass *acceleration F=m*a

NEWTON’S

SECOND LAW Of

MOTION

NEWTON’S THIRD LAW OF MOTIONWhenever one body exerts a force on another body , the second body exerts an Equal and opposite force on the first body .To every action there is an equal And opposite reaction .

NEWTON’S THIRD LAW OF MOTION

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MADE BY-PRIYANSHU KUMAR

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