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CREATED BY

NEWTON’S LAWS

F=G m1m2

r2

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ROLL NO : 52ROMIN CREATIONS

SEMINAR

UNIVERSAL LAW OF GRAVITATION

All objects in the universe attract each other.This force of attraction is directly proportional

to the product of their masses and inverselyproportional to the square of the distance

between them.

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Let m1 ,m2 be the two masses and r be the distance between them their

force of attraction F acting along line joning two centers of bodies.

F

m1 m2

r

F m1 m2

r2

G 6.67x 10-11Nm2/Kg2

SEMINAR

Every body continues to be in itsstate of rest or state of uniform motion in a straight line until it

is compelled by some external unbalanced force..

FIRST LAW OF MOTION

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SEMINAR

If the net external force on a bodyis zero ,its acceleration is zero.

Acceleration can be non zero only if there is a net external force on

thebody.

FIRST LAW

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NEWTON’S FIRST LAW IS ALSOKNOWN AS

“LAW OF INERTIA”

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Real world applications

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PERSON SITTING ON A CHAIR

The weight of the person acting down wards . The chair is appling a normal reaction in order to continue in state of rest.

RAINING

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NET FORCE DEVELOPED IS ZERO

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A skater boy

ismoving with a

uniform velocity

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THERE IS AROCK ACT

ASEXTERNAL

OBSTRUCTIONTO THE MOTION

EXTERNALOPPOSING

FORCE:

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SEMINAR

The rate of change of momentum of a body directly proportional to the applied force and take

place in the direction in which the force is acts

SECOND LAW OF MOTION

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F= k p t

MATHEMATICAL FORM

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F p t

k= constant of proportionality

F=k dp dtF=k d(mv) dtF=k m dv dt

F=ma

• A SEASONED CRICKTER CATCHES COMING

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• EVEN IF THEY ARE MOVING IN SAME SPEED

GREATER OPPOSING FORCE NEEDED FOR HEAVY VEHICLE THAN LIGHTER VEHICLE

A bullet of mass 0.04kg movingwith a speed of 90 ms-1 enters a

heavy wooden block and is stopped after a distance of 6cm.

What is the average resistive force exerted by the block on the bullet?

ANSWER

• The retaradation ‘a’ of the bullet (assumed constant) is given by

• a=-u2/2s• =90x90/2x0.6=-6750ms-2

• The retarding force,by the second law of motion,is

• F=ma• =0.04kg x 6750 ms-1=270N

impulsewhat-is the difference between momentum &Impulse?.Impulse =force x time duration=change of

momentumA large force acting for a short time to produceA finite change in momentum is called an

impulsive force

A bats man hits back a ball straight in the direction of the bowler without changing

its Intial speed of 12m/s.ifthe mass of the ball is of the ball is

0.15kg,determine the impulse impart to the ball. (assume linear motion of the ball)

ANSWER Change in momentum =(0.15x 12)-(-0.15X12) =3.6Ns

THIRD LAW OF MOTION

To Every Action ,There Is A Equal And Opposite Reaction

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Force always occur in pairs . Force on abody A and B is equal and opposite

to the force on the body B by A .There is no cause-effect relation implied inthe third law .

The force on A by B andthe force on B by A act at the same instant.

FAB= -FBA

(force on A by B) = (force on B by A)

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In time of lift –off of rocket

Reaction

Action

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ReactionAction

SWIMMING

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WALKING

Action

Reaction

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A shell of mass 0.020kg is fired bya gun of mass 100kg if the muzzle

speed of shell is 80m/s.what is the

recoil speed of gun?ANSWER:MV=-mv100xV=-0.020 x 80V=-0.020 X 80 /100=-0.016m/s

THANK YOU

ANY

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