1. Newton’s Laws of Motion
September 2016

2. Newton’s First Law of Motion
“The velocity of an object will remain constant unless a net force acts on it.”
Also called the Law of Inertia

3. Newton’s First Law (Law of Inertia)
An object in motion will stay in motion unless a net force acts on it.
If an object is at rest, it will stay at rest unless a net force acts on it.

4. What is inertia?
It is the tendency of the motion of an object to remain doing what it is already doing.
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The amount of inertia that an object has is dependent on the object’s mass. The more mass an object has the more inertia it has.

5. If an object has a large amount of Inertia due to larger mass:
It will be hard to slow down or speed up if it is moving
It will be hard to make it start moving if it is at rest
It will be hard to make it change direction

6. Examples of the effects of inertia:
Inertia causes a passenger in a car to continue to move forward even though the car stops
This is the reason that seat belts are so important for the safety of passengers
Inertia is the reason that it is impossible for vehicles to stop instantaneously

7. Examples of the affects of Inertia:
Inertia is the reason that it is harder to start pushing a wheelbarrow full of bricks than to start pushing an empty wheelbarrow. More mass = more inertia
Inertia is also the reason that it is harder to stop a loaded truck going 55 miles per hour than to stop a car going 55 miles per hour. The truck has more mass resisting the change of its motion and therefore, more inertia.