LAWS OF MOTION LAWS OF MOTION INTRODUCTION OF

LAWS OF MOTION

LAWS OF MOTION INTRODUCTION OF LAWS OF MOTION

LAWS OF MOTION A breeze the branches oftosomeone agive treeit to swing clearly, so some Ø To move football which isone at rest, has to kick it. throwaacauses ball upwards, has an upward push. external energy is needed to provide force to move a body from rest. Ø Likewise, an external force is needed to retard or stop motion. MOTION UNDER FORCE

LAWS OF MOTION Ø Ø Ø In these examples, the external agency of force is in contact with A magnet can attract an iron piece from a distance. the objects. So, it is clear that external agencies can also exert force on a body even from a distance. Force with contact Magnet CE FOR OUT H WIT TACT CON Force Iron piece MOTION

LAWS OF MOTION WHAT IS A FORCE? Ø Force is a pull or a push which generates or tends to generate motion in a body at rest, stops or tends to stop a body in motion, or tends to change the shape of the body. PUSH PULL

LAWS OF MOTION What is Internal Force? Internal force : Ø If the force applying agent is inside a system, then it is known as internal force. Ø It does not provide motion to the system.

LAWS OF MOTION Ex: Ø If you are sitting in a car and you push it, it doesn't move. Ø If you come out of the car and apply the same force, then it moves. External push moves the car Internal pu sh doesn’t mo ve the car

LAWS OF MOTION MCQ S 1) What is a force ? a) It is a pull or a push which tends to move a body. b) Stops or tends to stop a body in a motion c) Tends to change the shape of the body d) All of the above

LAWS OF MOTION 2) What is an internal force? a) Force applying agent is outside a system. b) Force applying agent is inside a system. c) It provides motion. d) Both (a) and (c)

LAWS OF MOTION WHAT IS INERTIA?

LAWS OF MOTION Ø Let us first learn about “The first law of motion”. It is also called as law of inertia. Ø To understand Newton's first law we have to learn about inertia at first. What is inertia. . ? Ø If the net external force is zero, i) a body at rest continues to remain at rest and ii) a body in motion continues to move with a uniform velocity. Ø This property of the body is called inertia.

LAWS OF MOTION Ø Inertia means “resistance to change”. Ex: - A ball at rest stays at rest, unless acted upon by a force. LE B A ST Inertia FORCE Mass MOTION

LAWS OF MOTION What is inertia? The man. All in the If things are lazy and they don’t things in the Let him go ahead Still itare. is stable Oh! he is not able to move it!! Things like to stay asdoes theythe picture is universe trying to, are want to move how lazy. with his trails. No object in this world movement a sofa. happen? starts moving on its own. is not willing He It can’t move because move. it istolarge in size

LAWS OF MOTION Even a small thing If we want to change the air resistance, roughness of the needs effort to Heofisan position object, an external able to move itcertain obstacles ground and change its position. asforce is needed. the ball iscoming small. in its path. If force is not acting on the ball, the ball will not stop and it keeps on moving and moving. GOOD! When a ball is kicked in space, it keeps on moving If there is no air resistance or Even for a small. But thing without stopping. inroughness of the ground or any Push and pull are the to move, it needsit astops lotobstacle ofthingsthe ball keeps on moving our atmosphere which make the objects move because of…. effort. and change their positions. and it can never stop.

LAWS OF MOTION

LAWS OF MOTION Ø Physicists have special name for this laziness. Things want to stay Things want to keep INERTIA in the same position doing what they are Inertia means laziness as they are. already doing. Ø If things are at rest, then they want to stay in rest. So, how can we say things are lazy? Ø If things are in motion, then they want to move on and on. Ø This is the Newton’s first law of motion. It states… Ø “Every body continues its state of rest or its state of motion until and unless an external force is applied”.

LAWS OF MOTION 1) What is inertia? a) It is a property of a body to oppose change in its state of rest or motion and vice versa b) It is the property of a body to change c) d) from rest It is the property of a body to change from motion none of the above MCQ S

LAWS OF MOTION 2) Which of the following is also called law of inertia? a) Newton’s first law of motion b) Newton’s second law of motion c) Newton’s third law of motion d) none of the above

LAWS OF MOTION NEWTON’S FIRST LAW OF MOTION

LAWS OF MOTION NEWTON’S FIRST LAW OF MOTION v. What According to Newton'sforce first law , figure? is the unbalanced in this Objects keep onchange doing “Every body bethis in its state of All objects resist theirtoin state What happened tocontinues theinskater what they are doing or uniform motion in a straightthis line of rest of uniform motion. Inertia means there is? askater natural Letthat us study the to understand a little better. figure. What mean by ? some unless to and until it isinertia compelled tendency of objects keep on does doing what external force ” they are doing. The skater changed his state from motion to rest. An external unbalanced force acted on v This law is also called as him in the form of an obstacle (stone). “Law of inertia”

LAWS OF MOTION INERTIA CAN BE CLASSIFIED AS The inability ofofaaa Theinabilityof The body totochange its INERTIAOF OFDIRECTION REST INERTIA MOTION bodyto changeits body state of motion until state ofby rest direction itsuntil own and unless an untiland andunlessan an external force acts externalforceacts external on it. onit. on

LAWS OF MOTION Being aware of Newton’s first law of motion we should wear a seat belt in the car. v First law talks about how to overcome inertia when an unbalanced force is applied.

LAWS OF MOTION MCQ S 1) Which law of Newton is called the law of equilibrium? a) Newton’s first law of motion b) Newton’s second law of motion c) Newton’s third law of motion d) Newton’s law of gravitation

LAWS OF MOTION 2) You are thrown outwards when your car suddenly takes a turn. Which law of Newton is involved in this? a) third law b) second law c) first law d) law of gravitation

LAWS OF MOTION Thank you…