This law states that the more mass an object has the more force you need to move it. Objects have what Newton called "Inertia (difficult to moveness). If something has a large amount of mass, its' inertia great and it is hard to move (see the picture above). If an object has a small amount of mass, its' inertia is small, it is easy to move.

Sometimes people use this way to explain Newton's Second Law.

F=M*A (Force = Mass of an object *(times) Acceleration of an object). This tells us the more mass an object has, it takes more force to move it and more force to stop it.

Examples:

1.) If a train is moving at 50 mph. It has a lot of force because its' mass is so large. Compared to car moving a 50 mph. It would take a lot to stop the train.

2.) If I wanted to move a pencil, I would not have to use a large amount of force, because its mass is small. Now, if I wanted to move a metal cabinet, I would need to use a great amount of force because its' mass was great.

3.) It takes more force to launch a 100 pound rocket than a 10 pound rocket. Remember this when you build.