User:Ajina Steephan

NEWTON'S FIRST LAW OF MOTION

Think about the situations ...

1. Do this activity...

• Take a glass tumbler , a piece of cardboard and Rs 10 coin .
• Place Rs 10 coin on the cardboard piece and keep that on the mouth of the tumbler .
• Give a horizontal flick to the cardboard with your finger .

https://commons.wikimedia.org/wiki/File:Cup_and_Coin_Activity.jpg#

2. When we are standing in a bus and the bus begins to move suddenly ...

3. While travelling in a bus , the driver applies brakes suddenly ....

What will happen in these cases ... ???

• Why does the cardboard move away when it is flicked with your finger ?
• Why does the coin fall vertically inside the tumbler ? Why doesn't the coin move with the cardboard ?
• Why do we fall backward when the bus suddenly start moving ?
• Why do we fall forward when the driver suddenly apply brakes ?

All these questions are answerable on the basis of NEWTON'S FIRST LAW OF MOTION .

Newton studied Galileo's ideas on force and presented three fundamental laws that governs motion of bodies . These three laws are known as Newton's laws of motion . Now we are going to discuss about NEWTON'S FIRST LAW OF MOTION .

Newton's first law of motion is stated as :

' An object remains in it's state of rest or uniform motion in a straight line unless it is compelled by an applied unbalanced force '. First law of motion is also known as The Law of Inertia . Because , first law can also be stated as ' all objects resist a change in their state of rest or uniform motion '. The tendency of objects resist the change in it's state of rest or uniform motion is called INERTIA .

The above situations can be explained by Newton's first law of motion . In the activity , because of the applied unbalanced force , the cardboard is moving away from it's state of rest . Due to the inertia of rest the coin does not move with cardboard and because of the absence of support the coin falls vertically downward . When the bus move suddenly , we tend to fall backward . This is because the sudden start of the bus brings motion to the bus and our feet in touch with the floor of the bus . But the rest of our body opposes this motion because of its inertia . The experience that we come across while travelling in a bus and when the sudden brake is applied can also be explained on the basis of Inertia . With the sudden application of brakes , the bus slows down but our body tends to remain in the state of motion because of its inertia .