# Newton's Laws of Motion

## Newton's 1st Law

An object at rest will stay at rest and an object in motion will stay in motion unless acted on by an external force. This is also referred to as inertia, which is an object's tendency to resists a change in motion.

This means that an object will not stop moving, until a different force is applied to it.

For example, a car will experience this law if it suddenly collides with a brick wall while at a constant velocity.

Volvo - Crash Test - Car crashing into a rock wall

## Newton's Second Law

This law suggests that Force = Mass x Acceleration.

This could also work in the opposite such as Mass = Force/Acceleration and Acceleration = Force/Mass.

The original equation proves that more force applied to an object would make it move faster and less force on the same object will result in a slower speed.

Word Problem: A car with a mass 200 kg is moving with an acceleration of 5 m/sec2.

You would multiple 200 by 5 and get an answer of 1000 Newtons.

Below is a video of a strong Russian man pushing a car. See if you can figure out the force he's appealing to the car:

This Russian gym guy is pushing a car backwards so strong that the car can make a burnout

## Newton's Third Law

For every force there is an equal and opposite force, for every action there is an action and an equal and opposite reaction.

This means that there is a reaction for every action that takes place on earth. If something is pushed down, something else must be pulled up.

If you jump off of a diving board for instance. As you push down, an opposite force of the board pushing up will occur. Causing you to jump into the pool.

Dog jumping off of diving board

## Vocab Words to Know:

Force: A push or a pull.

Acceleration: A change in velocity over a given amount of time.

Mass: The amount of matter in an object.

Inertia: An object’s tendency to resists a change in motion.