What is Newton’s First Law of Motion? [Simple Explanation]

Will this ball move?

Will this ball stop?

You might be thinking that it’s a simple question !!

Ball will move when someone kicks it, right?

Okay, But what about the moving ball, how will it stop?

The answer is simple !!

Either you can stop it or with the help of friction, it will stop.

In the above line, what do you mean by kick?

It is nothing but an external force.

Similarly, what can you say about friction?

This is also one type of external force.

In short, External force is required to put a stationary body in motion or stop a moving body.

But, what happens when a boy is moving on a skateboard with uniform speed, still an external force is required to keep a skateboard moving?

Will this skateboard keep moving forever?

Now you know, it’s not that easy to answer this question.

In the 17th century, Issac Newton answered this question in a very simple way which is further known to us as Newton’s first law of motion.

Newton’s first law of motion states that:

“An object at rest remains at rest and object in motion remains in motion unless an unbalanced force acts on it”

Do you know what is another name for Newton’s 1st law of motion?

Newton’s first law of motion is also known as the Law of inertia.

Newton has given these three laws of motion:

All the Newton’s three laws of motion together laid the foundation of classical mechanics.

Understand newton’s first law with examples

“An object at rest remains at rest and object in motion remains in motion unless an unbalanced force acts on it”

What do you understand by this statement?

Well, I know such statements are quite complicated to understand.

Don’t worry,

Check out some real life examples of newton’s first law of motion mentioned below.

You will surely understand the meaning of the whole statement of newton’s first law.

Okay, So let’s move on to the examples…

#1 Bicycle ride

Both these boys are about to go for a ride along with their bicycles.

As you can see, both the boys (along with their bicycles) are initially at rest.

What do you mean by this?

It means that the object which is at rest remains at rest position only.

The object considered here is the bicycle. (You can consider either boy or bicycle as an object)

The bicycle will accelerate forward only when both the boys apply forces on it.

Now, when the bicycle comes in motion, see what happens…

As you can see, the bicycle moves forward when both the boys exerts force on it with their legs.

In short, the bicycle comes into motion when an external force is applied to it.

Now what happens?

Will both the bicycles keep moving forever?

You might be thinking, the bicycle will stop when the brakes are applied to it right?

Yes, you are right. But, what if there were no brakes?

See, the below image…

When one obstacle comes in between the road, the boy can’t control his bicycle. (As the speed of the bicycle is too high)

Now, here comes the first law,

When the bicycle strikes with the obstacle, it means that an external force acts on the bicycle.

(This external force is nothing but an unbalanced force only)

Only because of this unbalanced force, the bicycle stops.

Conclusion is,

Bicycle which is at rest remains at rest, and the bicycle which is in motion remains in motion. (Unless an unbalanced force acts on it)

#2 Bowling

Newton’s first law of motion is clearly seen in the game of bowling.

Have you played this game?

If you have played, you already know how it works, right?

See this image…

As this boy holds the ball in the hand, the ball is initially in rest condition.

Now, tell me one thing… will this ball move on its own?

Obviously no, right.

The ball comes into motion when the boy throws it with his hand.

In short, the ball which is at rest remains at rest only.

As in the first half of newton first law of motion it is clearly mentioned that,

Object at rest remains at rest. (In this case, consider the ball as an object)

The ball comes in motion, only when an external force is given to it.

Now, what happens when the ball comes into motion?

You can see, the ball is moving towards the pin.

In short, the ball which is in motion remains in motion until it hits the pin.

See what happens when the ball hits the pin…

When the ball hits the pin, an external force acts on the ball.

Now, here comes the newton’s first law,

When the ball hits the pin, it means that an external force acts on the ball.

(This external force is nothing but an unbalanced force only)

Only because of this unbalanced force, the ball stops.

Conclusion is,

The ball which is at rest remains at rest, and the ball which is in motion remains in motion. (Unless an unbalanced force acts on it)

#3 The Car

Do you know how Newton’s first law is applied while starting or stopping a car?

First of all, tell me, how will you state Newton’s first law of motion?

“An object at rest remains at rest and object in motion remains in motion unless an unbalanced force acts on it”

Now, let’s understand the real life situation.

Imagine you are going somewhere in the car.

Now, the car does not start on its own, right?

See this,

As you can see, initially the car is in rest position.

Unless the boy starts the car, the car remains in rest position only.

In short, the car starts when an external force is given to it.

Now what when the car comes into motion?

Again the car which is in motion remains in motion only. (Unless an unbalanced force acts on it)

As the traffic signal turns to red, the boy applies the brakes and the car stops.

Again, here comes the newton’s first law,

When the boy applies the brakes, it means that external force is applied on the car.

(This external force is nothing but an unbalanced force only)

Only because of this unbalanced force, the car stops.

So the conclusion is,

The car which is at rest remains at rest, and the car which is in motion remains in motion. (Unless an unbalanced force acts on it)

#4 Moving Scooter

In this example, I have clearly explained how Newton’s first law is applied while driving a scooter.

Let’s make it simple.

One boy is going to the market on his scooter.

As the scooter is initially in the rest position, it does not start on its own, right?

See this,

As seen above, here also…

Unless the boy starts the scooter, the scooter remains in rest position only.

Therefore, the scooter starts only when an external force is given to it.

In short, the scooter which is in rest remains in rest only. (If no external force is given to it)

Now when the scooter comes into motion, see what happens…

Now when the boy starts his scooter, the scooter and the boy both are in motion right?

(You can consider either boy or scooter as an object)

Now this scooter which is in motion, remains in motion only. (Unless an unbalanced force acts on it)

Now, when one obstacle (Stone) comes in between the road, see what happens…

As the stone comes in his way, the boy applies the brakes.

As his scooter’s speed is too high, he can’t control his scooter and falls down.

This shows the presence of newton’s first law,

When the boy applies the brakes, it means that external force is applied on the scooter.

(This external force is nothing but an unbalanced force only)

Only because of this unbalanced force, the scooter stops.

In short,

Scooter will not change its behavior unless an unbalanced force acts on it.

(Whether the scooter is in rest or in motion)

#5 Ice Hockey

Here, I have explained the application of Newton’s first law with example of ice hockey. (You’ll definitely love it)

As the puck is initially in rest condition, it will remain in rest condition only.

Now, this puck will not move on its own, right?

Obviously No.

As you can see, the puck comes in motion when the player hits it with the hockey stick.

It means that an external force is given to it with the hockey stick.

(This external force is nothing but an unbalanced force only)

Again, this puck which is in motion remains in motion only. (until some another player hits it)

When the player hits the puck, unbalanced force acts on the puck.

Only because of this unbalanced force, the puck stops.

So the conclusion is,

The puck will not change its behavior, unless an unbalanced force acts on it.

(Puck which is at rest remains at rest, and the puck which is in motion remains in motion)

#6 Tomato ketchup

When you ate pizza, last time?

There is no doubt that almost everyone has eaten pizzas.

Do you want tomato ketchup along with the pizza? (Well, I need it)

You know what,

Newton’s first law can be easily understood while applying the tomato ketchup on pizza.

You have definitely seen this example of Newton’s first law of motion.

Have you ever faced difficulty while removing tomato ketchup?

(Let me know in the comments, if you have experienced this)

The ketchup comes out easily when you hit the bottle from the back side.

In short, the ketchup comes out when an external force is given to the bottle.

(This external force is nothing but an unbalanced force only)

Only because of this unbalanced force, the ketchup comes out from the bottle.

Conclusion is,

The ketchup inside the bottle remains as it is, unless an unbalanced force acts from the back side.

(Which shows the presence of newton’s first law)

#7 Pool

Have you played the pool?

Okay, that’s not important whether you have played or not.

But, do you know how Newton’s first law is applied while playing the pool?

See this…

As you know, the ball is initially at rest condition.

The ball comes in motion, when the girl hits the ball with the pool stick.

In short, the ball will remain in rest position only, if no external force is given to it.

Now, when the ball comes in motion see what happens…

Will this ball keep moving forever?

Obviously no, right. (As the friction reduces its speed)

The ball will only stop, when it strikes with another ball or with the edges of the table.

Conclusion is,

The only reason which puts a stationary ball in motion and stops a moving ball is the external force.

(This external force is nothing but an unbalanced force only)

Therefore,

The ball at rest remains at rest and the ball in motion remains in motion unless an unbalanced force acts on it.

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Don’t you think, is easy to remember the statement of Newton’s first law of motion?

(Let me know by leaving a comment)

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