Forces Forces and and Newton Newton

Newton is famous for discovering the Force of Gravity, but he also created 3 important Laws of Motion!

Newton’s 1st Law of Motion: An object in motion will stay in motion, and an object at rest will stay at rest, unless acted on by a force. Translation: Force is what starts and stops motion!

Examples of Newton’s 1st Law: * a marble will not move unless forced. * once a marble is moving, it doesn’t stop until forced to!

* if you don’t wear your seatbelt, you have no force to stop you when the car crashes! since you keep moving, you fly through the windshield! (and DIE)

* Things dropped from a moving vehicle don’t fall straight down! * they keep moving forward until another force stops them!

Special word to explain Newton’s first law: INERTIA! Inertia = resistance to change in motion (things don’t want to start moving if they are stopped, or stop moving if they are moving)

Newton’s 2nd Law of Motion: Force = mass X acceleration = x This means that the magnitude of the force is decided by how big and heavy an object is, and how fast it is moving!

This makes sense: big, heavy objects have a lot of force. An elephant doesn’t have to move fast! Small objects can have a lot of force if they are moving FAST. a bullet thrown by hand does nothing, but shot at high speed it can kill!

Newton’s Third Law of Motion: For every action, there is an equal and opposite reaction. Translation: If you push, you also get pushed back!

This is why we are able to jump-- when we push the ground, it pushes back!