What to do… Open your note packet to page 29. Answer this question in the “Think About It” If two people are pushing on a box with the same amount of force, in opposite directions, will the box move?

Newton’s First Law Chapter 20 Section 2 SPI: 11.4- Identify and explain how Newton’s laws of motion relate to the movement of objects.

Preview

Newton’s 1st Law An object at rest tends to stay at rest and an object in motion tends to stay in motion unless acted upon by an unbalanced force. demo

An Object at Rest Identify an object at rest Ex: chair on the floor, a plane on a runway These objects will not start moving until a is exerted on them. Ex: push or pull You tend to fall backward when your school bus starts to move.

An Object in Motion An object moving at a certain velocity will continue to move forever at the same speed and in the same direction unless some unbalanced force acts on it. Ex: Riding in your car. When the car comes to a stop you would continue to move in the direction of the car, however your seatbelt stops you.

Balanced Force Equal forces in opposite directions produce no motion

Unbalanced Force Unequal opposing forces produce an unbalanced force causing motion

Because there’s almost always an unbalanced force acting upon them. If objects in motion tend to stay in motion, why don’t moving objects keep moving forever? Because there’s almost always an unbalanced force acting upon them. A book sliding across a table slows down and stops because of the force of friction If you throw a ball upwards it will eventually slow down and fall because of the force of gravity

Inertia The tendency of an object to resist a change in its motion Inertia can be described as the tendency of an object to keep doing whatever it’s doing.

Which vehicle has more inertia? MASS & INERTIA The more mass an object has, the more inertia the object has. Therefore an object with a small mass will have a small inertia Bigger objects are harder to start & stop Which vehicle has more inertia?

Inertia

The push of the stopped car. The truck is in motion. What is the force that causes it to stop? The car is at rest. What is the force that causes it to move? The push of the stopped car. The push of the truck.

DO!! The ball will stay at rest until the boy kicks it with his foot

Keys to Understanding At LEAST 5 complete sentences Summarize the main points of the lesson Describe in detail the important ideas Write about concepts you want to remember This should be helpful to YOU!