__Advanced (Level 2)__

## Newton's Laws of Motion

Sir Isaac Newton was an English Physicist and Mathematician who lived in the 17th century. He wrote about the connection between Motion and Force in what is known as

**Newton's Three Laws of Motion.**## First Law of Motion (Inertia)

If an object (or a thing) is stopped it will not move without using Force

If an object is already in motion, it will keep moving in the same direction until some kind of Force is used to stop it.

Inertia

**Inertia**tells us how hard or easy it will be to move something. A heavier object needs more Force to move and is said to have more

**Inertia**whereas a lighter object is said to have a less

**Inertia**.

## Second Law of Motion.

In the swing experiment you also observed moving the swing or the toy wagon depended on how heavy or light it was. Also, how far or near it went depended on how much Force was applied.

The amount of Force needed to Move something depends on how heavy or light it is - Mass. (Pushing a grown-up in the swing is a lot more difficult than pushing an empty swing. )

The amount of Force also depends on how fast you want the motion to speed up - Acceleration. (e.g. you need to put more Force to push an empty swing, if you want it to go higher)

## What is Mass ?

If you remember from the "All About Matter" topic, Mass is the shape and size of Matter.

On Planet Earth the mass of all matter is the same as its weight.

On Planet Earth the mass of all matter is the same as its weight.

## What is speed ?

Speed is the distance traveled by an object divided by the time taken to cover that distance.

For e.g. Suppose your school is 4 miles from home and it takes your 5 minutes to get to school, by car, in the morning, assuming the car does not make any stops in between.

The car traveled at a speed of 4 miles/ 5 minutes = 0.8 miles/minute.

How about calculating the car's speed in miles per hour (mph)?

There are 60 minutes in 1 hour.

Q) If the car traveled 0.8 miles in 1 minute, how many miles did it travel in 60 minutes?

The answer is 48 miles. So the car traveled at a speed of 48 miles per hour or 48 mph.

For e.g. Suppose your school is 4 miles from home and it takes your 5 minutes to get to school, by car, in the morning, assuming the car does not make any stops in between.

The car traveled at a speed of 4 miles/ 5 minutes = 0.8 miles/minute.

How about calculating the car's speed in miles per hour (mph)?

There are 60 minutes in 1 hour.

Q) If the car traveled 0.8 miles in 1 minute, how many miles did it travel in 60 minutes?

The answer is 48 miles. So the car traveled at a speed of 48 miles per hour or 48 mph.

## What is Acceleration

**Acceleration**is how fast you want something to speed up.

eg. When you are sitting in a car observe how it gradually speeds up from a stopped position. This gradual speeding up is called

**Acceleration.**

The car slowing down to a lower speed or to come to a complete stop, is called Negative Acceleration or Deceleration.

You can observe this same thing while riding your bike or your scooter or even while running.

Newton's Second Law of Motion states that Force depends on Mass and Acceleration. If you know the value for Mass and for Acceleration, you can calculate the Force by using this equation

We'll explore this Math to calculate Force in subsequent pages.

**Force = Mass x Acceleration**(Newton's 2nd Law)We'll explore this Math to calculate Force in subsequent pages.