OUR SCIENCE PROJECT

MUSKAAN KHANNAYATHARTH

YASH GUPTAAMBIKA BANSAL

BHANULAKSHAY SHARMARAMIT CHAURASIA

we take this unique opportunity to

express our deep sense of gratitude & indebtedness to my respected guide

Mrs. GEETA SETIA[PHYSICS TEACHER] for her valuable guidance for completion of

this project. Last but not the least, we extend our hearty love, affection & thanks to our

friends who helped us in one or the other way for successfully completing our PPT

project.GROUP 3

[CLASS-9TH D]FORCE & LAWS OF MOTION

CONTEN

TS

FORCE

LAW OF INERTIA

SECOND LAW OFMOTION

THIRD LAW OF MOTION

CONSERVATION OF

MOMENTUM

FORCE IS AN EFFORT IN THE FORM OF PUSHING PULLING, STRETCHING , COMPRESSING ETC.

It may move a body at rest.It may stop a moving body It may change the speed , direction , shape or size of the body.

If the resultant of all the forces acting on a body is zero , the forces are called BALANCED FORCES.

If the resultant of all the forces acting on a body is not zero , the forces are called UNBALANCED FORCES

According to 1st law of motion . A body remains in rest or inA state of uniform motion until an external unbalanced force is applied on it.

It is the natural tendency of an object to resist a change in its state.

INERTIA OF REST,DIRECTION,MOTION, :-

1. When we shake a branch of mango tree, the mangoes fall.

2. When a car passes through mud, the rotating wheels throw out mud tangentially.

3. When a bus stops suddenly, a person sitting inside tends to fall forward.

When a running horse suddenly stops, the rider falls forward.

When a horse suddenly starts moving the rider falls backward.

We hit carpet with a stick to remove the dust.

Athletes run some distance, before taking a long jumps .

A man jumping form a moving train may fall down.

Momentum of a body is the product of its mass & velocity.

According to Newton's second law of motion, the rate of change of momentum of a body is directly proportional to the force applied, & this change takes place always in the direction of the force applied.

1.While catching a cricket ball, a player pulls his hands backwards to prevent injury to his hands.

2.In the athletic event ‘high jump’ , the athletes are made to fall either on a cushioned bed or on a sand bed.

3.All the cars, these days are provided with seat belts for the passengers, which are rightly called safety belts.

When catching a ball a cricket player lowers his hands to save himself from getting hurt.

Cars, busses, trucks, bogies of the train, etc. are provided with a spring system to avoid server jerks.

Bogies of the train are provided with buffer to avoid server jerks during shunting of trains.

A person falling on frozen ice is likely to receive more injuries than one falling on kuchcha floor.

China wares are wrapped in straw or paper before packing.

According to Newton's third law of motion,to every action, there is always an equal & opposite reaction These forces act on different objects & never cancel each other. Each force produces its own effect.

1.While swimming , a swimmer pushes the water backwards with his hands and feet (i.e. action) & water pushes the swimmer forward with the same force of reaction.

2. It is difficult for a fireman to hold a hose, which ejects large amounts of water at a high velocity.

When a man jumps from a boat to the shore, the boat slightly moves away from the shore.

When a bullet is fired from a gun, the gun recalls or gives a kick in backward direction.

Rocket works on the principle of conservation of momentum.

If some one left on a frictionless floor desire to get out of it, he can do so by blowing air out of his mouth.

WHEN TWO BODIES COLLIDE WITH ONE ANOTHER, THE VECTOR SUM OF THEIR MOMENTA REMAINS EQUAL TO THE SUM OF MOMENTA BEFORE THEIR COLLISION.

1. Rocket moves upward in a direction opposite to the direction of escaping gases, with momentum equal to the momentum of the escaping gases.

2.When a bullet is fired from a gun, the gun recoils, i.e. , the gun moves backwards. The recoil velocity v2 of the gun is v2 = -m1v1

Where v1 is velocity of the bullet of m1 & m2 is mass of the gun.

m2

1. Why cups or china wares are packed in straw?2.How a horse is

able to pull a cart?

3.Is force a scalar or vector quantity?

•INTERNET•REFERENCE BOOKS •TEXT BOOK

THANKS FOR GIVING US

YOUR PRECIOUS TIME AND

BEING SO PATIENT