1. Newton’s Laws of Motion

2. Law #1 – Inertia An object at rest will remain at rest and an object in motion will remain in motion at constant speed and in a straight line unless acted on by an unbalanced force.

3. This means that unless an unbalanced force affects an object, it will continue doing what it is doing – either sitting still or moving! Newton named this law The Law of Inertia “Inert” means not moving So inertia is an object's tendency to stay still!

4. Inertia Depends on Mass The more mass an object has, the harder it is to get it to move or to stop! This is why seatbelts save people – they prevent you from maintaining a speed of 60-70 miles an hour when the car suddenly stops!

5. Law #2 - F = m X a The acceleration of an object depends on the mass of the object and the force applied. Force Mass Force

6. It is harder to accelerate a more massive object Force Mass  The more force is applied, the more acceleration will occur – depending on mass! Mass Force

7. For example… If you throw a bowling ball as hard as you throw a baseball, it will not accelerate as much - it has more mass! 150 N

8. This equation works just like the speed equation… If an object accelerates at 10 m/sec with a mass of 50 kg, what is its force?  F= M x A  F = 50 x 10  F = 500 Newtons of force! If a 1 kg basketball is thrown with a force of 80 N, what is its acceleration? If a cow moves with an acceleration of 5 m/sec/sec and has a mass of 200 kg, how much force is needed?

9. Law #3 – Action-Reaction Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force to the first. Force from hot gases Forward thrust

10. All forces act in pairs! Whenever one force acts, a second must act. THIS IS TRUE FOR EVERY FORCE IN THE UNIVERSE!!! When you jump off of the ground, you push down and the ground pushes you back up. If an astronaut floats away from his ship, he can throw a wrench in the opposite direction, and be propelled back toward the ship.