Motion & Forces Motion occurs when an object travels from one point to another. Position describes the location of an object. A Reference point is a location to which you compare the motion of another object. (Ex: The car drove past the tree. The tree is the reference point.) Speed (s) is a measure of how far something travels (distance- d) in a given amount of time (t). speed= distance ÷ time s= d÷t Velocity is speed in a specific direction. Acceleration is the rate at which velocity changes. In science, acceleration refers to increasing speed (positive acceleration), decreasing speed (negative acceleration, or changing direction. Centripetal force is a force that causes an object to accelerate in a circular path. Centripetal acceleration is acceleration in a circular motion.

What is a force? A push or pull, a force changes the motion of an object, force = mass x acceleration Measured in Newtons (N) Types of Forces Contact force: created between two touching objects (pushing, pulling, holding a pencil, hugging someone, etc) Gravity: force of attraction between two objects, Earth’s gravity pulls on all objects Friction: a force that resists motion between two surfaces that are pressed together

Vectors Like velocity, force is a vector. That means it has size (magnitude) & direction. Magnitude = amount or strength of the force Measured in Newtons A vector is an arrow used to show the direction & size of a force. The arrow points in the direction of the force. The length or thickness of the arrow represents the size or magnitude of the force.

1st Law of Motion (Law of Inertia) An object at rest will stay at rest, and an object in motion will stay in motion at constant speed, in the same direction, unless acted upon by an unbalanced force. Inertia is the tendency of an object to resist changes in its velocity: whether in motion or motionless. Ex. Golf Ball sitting on a Tee Once airborne, unless acted on by an unbalanced force (gravity and air resistance) it would never stop! Unless acted upon by an unbalanced force, this golf ball would sit on the tee forever.

For every action, there is an equal and opposite reaction. 2nd Law The acceleration of an object depends on the mass of the object and how much force is applied, or F=ma. 3rd Law For every action, there is an equal and opposite reaction.

Net Force Usually, more than one force is exerted on an object at the same time. The sum of all forces acting on an object is called the net force. Balanced Forces: Net force = zero, No change in motion, (object is not moving) Unbalanced Forces: The object is moving, There is a net force acting on an object, Causes a change in motion. If forces are in the same direction: add the forces together to find the size & direction of the net force. If the forces are moving in opposite directions: subtract the forces, the object will move in the direction of the larger force.

You Try It: Net Force

You Try It: Net Force

12) If you blow up a balloon, and then release it, the balloon will fly away. This is an illustration of Newton's first law. B) Newton's second law. C) Newton's third law. D) Galileo's law of inertia

What is the net force acting on the ball?

Motion Output When you are finished with the lesson review, turn it in to the basket and pick up an output foldable. Go get your science notebook. On the next empty page after the motion input, title it “Motion Output,” date 8/27/18. Add this entry to the table of contents. Glue foldable to this page. Fill in all information, make sure all pictures are colored. Show Mrs. Walker your work before turning in your notebook to the basket.

TODAY YOU NEED: Headphones, colored pencils, & notes folder Log in to the chrome book. Go to think central. Log-in to think central. STOP Turn off your sound on the computer and wait for instructions!

Today you need: colored pencils and notes folder What is the net force acting on the book? Are the forces balanced or unbalanced? How do you know? PICK UP YOUR SCIENCE NOTEBOOK WHEN YOU ARE FINISHED WITH THE QUESTIONS!

LOG IN TO THINK CENTRAL ONLY IF YOU DID NOT FINISH YESTERDAY! Take your unit quizzes. ***While you are working quietly, you will be called to the hallway for the quick lab. *** GO GET SCIENCE NOTEBOOK & Pick up a foldable if you do not have one. Title “Motion Output,” date 8/27/18, add to table of contents. Glue to output page. You may use your computer to research ideas and look up answers to your foldable. **Check your notebook with Mrs. Walker before turning in.** Go to My Library, click on Student Resources, Unit 1 Lesson 3, Click on Virtual lab. Do your best to complete all questions, show Mrs. Walker your lesson tracker for extra points on your quiz grade.

Today you need: Textbook and Notes Folder What is the Net Force acting on the box? Which forces are balanced? Which forces are unbalanced? 25 N 15 N 5 N

Work on your study guide Work on your study guide. When it is finished, complete your science notebook. GO GET SCIENCE NOTEBOOK & Pick up a foldable if you do not have one. Title “Motion Output,” date 8/27/18, add to table of contents. Glue to output page. **Check your notebook with Mrs. Walker before turning in.** Raise your hand, show Mrs. Walker your completed work, then you may get a computer off the cart. Go to Think Central and log in, click My Library, click on Student Resources, click on Unit 1, click on Lesson 3, Click on Virtual Lab: Sliding downhill. Do your best to complete all questions, show Mrs. Walker your lesson tracker for extra points on your quiz grade.

Make sure your study guide is ready to turn in for a grade. Today you need: Study Guide **Bring materials to work on science notebook if you aren’t finished! Study for your test! Make sure your study guide is ready to turn in for a grade.

GO GET SCIENCE NOTEBOOK & FINISH INPUT & OUTPUT. **Check your notebook with Mrs. Walker before turning in.** Extra Credit: Go to Think Central and log in, click My Library, click on Student Resources, click on Unit 1, click on Lesson 3, Click on Virtual Lab: Sliding downhill. Do your best to complete all questions, show Mrs. Walker your lesson tracker for extra points on your quiz grade.