 # Newton's Laws Of Motion | class 9 science chapter 9

## Newton's law of motion:- Based on the studies of  a motion, Sir Issac Newton, one of the greatest scientist of all time had given  three laws of motion, which is discussed below: ### i) 1st law of Motion:-This law is also known as law of inertia, which states that,  an object remains in its state of rest or of uniform motion in a straight line unless compelled to change that sate by an applied force.

In other words, it can said that the tendency of an object to remains in its state of rest of or in a uniform motion, unless it is disturbed by an external  applied force.

Newton's law of motion with examples:
To understand the law more deeper,lets illustrate two situation:

### i)Situation I:-

Let us illustrate a city bus moving with a uniform velocity of about 35km/hr throughout  the city. A few moments later, the city bus has to go through a narrow bridge,  and gradually decreases the speed of the bus.

But meanwhile the passenger who were at uniform  motion of about 35km/hr, their body tends to remains in motion and the body gives and upward jerk to the passengers, due to change in motion, which satisfies Newton's 1st Law Of Motion.

ii) Situation II:-
Have you ever observed or rode  Rollar coaster, you  will be able to see that when its starts moving fast it  gives an backward jerk to the people riding it, in other words we can say that our body remains in rest before riding in  it, and tends to remains in its state of rest, which also satisfies Newton's 1st Law.

### Newton's  2nd law of motion states that the rate of change of momentum is always proportional to the applied unbalanced force and act in the direction of  force.

Newton's law of motion examples:
To understand the topic more deeply, lets illustrate a  two situation which are given below:

### Situation I:- Let us illustrate   a car with dead battery. In our everyday life we  always see when a car battery is dead, the car or a vehicle needs to be pushed to restart the  engine.But the facts is that, did we asked  our self , how the car starts when it is pushed with force?

Well the facts is in Newton's 2nd law of Motion, in this situation  the car attains some momentum or the car engine is  restarted, only due to the applied unbalanced force from behind, which satisfies Newton's 2nd law of motion.

### Situation II:- In our day to day life,  did we ever noticed that how  does our bicycle runs? Well its runs only due to Newton's 2nd law.

The fact is that, when  a bicycle is at rest there is no movement in it. TO move it or to ride it, we need to apply a unbalanced force in it, thereafter  it  wheel starts rotating and  attains some momentum, which satisfies Newton's 2nd Law.

### 3rd Law Of Motion :-Newton's 3rd Law OF Motion states that when one object  exert some  quantity of force on another object , the  second object on the instant  exerts a equal quantity of force on the first object  in the direction opposite to the first object.      In simple words we can say that  to every  action done by a body , there is an equal and opposite reaction from the another body from opposite direction with  same force.

To understand the topic more, lets try to illustrate two situation:-

i) Situation I:- In our daily we saw many action  movies where use of gun is usual, but did we observe while firing the gun, the gun exerts some backward force, or the gun exhibits recoil while firing.Why does this  happen?

Well the correct answer is from Newton's 3rd Law Of Motion, here  a person  fires the gun  with some quantity of force and the bullet is emitted from the gun.But meanwhile the gun recoils with same quantity of force as the bullet leaves the gun in the direction opposite to the emitted bullet.. which satisfies Newton 3rd Law Of Motion.

ii) Situation II:-  Let us illustrate a archer with bow and arrow, aiming to her target,  stretched the  bow and  the emitted arrow hits the target.But did we observe how did it originally works?

Well it also works on Newton's 3rd Law of Motion. When the archer stretched the bow in backward direction, it meant some quantity of force is applied by the archer on the bow in the backward direction and on the  contrary the  bow  emits the arrow with the same force on which the archer exerts on the bow , in the direction opposite  to it, which satisfies Newton's 3rd Law.

It covers all the  topics such as  "newton's law of motion class 11"  "newton's law of motion class 11th" "newton's law of motion 2" "what is newton's third law of motion"

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#### 1 comment

1. Awesome brother

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