7th Grade Review for Newton’s 3 Laws of Motion Forces that are At-a-Distance

How do you get something to move. How do you get something to stop How do you get something to move? How do you get something to stop? How does mass affect these?

Vocabulary Newton=Isaac Newton, also the unit to measure force “You have to FORCE me to eat a fig NEWTON” Mass=the amount of matter in an object=g or Kg Acceleration=change in speed, slowing down or speeding up Force=push or pull Unbalanced force=change in motion Motion=movement Inertia=an object will do what it is already doing unless its’s pushed or pulled Friction=resistance to movement, causes heat

Force is measured in Newtons (N) “You have to FORCE me to eat a fig NEWTON! Because they are ewww!”

Newton’s 1st Law: Inertia If you are on the couch watching Netflix, you want to stay on the couch. Someone will have to force you to get up and move. That will take energy!

Newton’s 1st Law: Inertia If you are skateboarding and you are moving forward quickly, you and the skateboard will keep moving forward unless you hit a rock with the wheel, then…

Newton’s 1st Law: Inertia If you are in a vehicle, always wear a seatbelt because of inertia! If you hit an object while traveling fast, then your body wants to keep moving…through the windshield

Newton’s 2nd Law: F=ma The more mass an object has=the more force the object has. 5 kg 10 kg

Which lineman will hit with more force (if they travel at the same speed? Why?

Newton’s 3rd Law: Action/Reaction

Newton’s 3rd Law: Action/Reaction When 2 objects interact, each one puts a force on the other one, and these forces can transfer energy between the two objects.

Newton’s 3rd Law: Action/Reaction

Newton’s 3rd Law: Action/Reaction

Newton’s 3rd Law: Action/Reaction

Newton had a law for this… Newton’s 3rd Law says: Whenever Thing 1 pushes on Thing 2, Thing 2 pushes back on Thing 1 in the opposite direction with the same force

Unbalanced force=Movement or Motion Free Force Diagrams: shows all forces acting on an object

Mass, Weight, and Gravity Which ones change when you go to the moon? Which one changes when you go on a diet? Which one is measured with a spring scale? What is a spring scale? What units do they each have? Pounds? Grams? Newtons?

What are the differences among mass and weight and gravity? Measures how much matter is in an object Measured in grams Changes when you remove part of the object or add to the object

What are the differences among mass and weight and gravity? Measures how much gravity pulls on something Measured in Newtons Changes when you go to another planet or by changing the mass of something.

What are the differences among mass and weight and gravity? Measures the force of attraction between the mass of two objects in a system. Measured in Newtons Changes when the mass of a planet changes OR When the distance between the planets change.

Forces that act AT-A-DISTANCE and are UNSEEN Magnetism Static electricity Gravity

Edited and short version of “Bill Nye” magnetism (part 1) 5:38 minutes https://www.youtube.com/watch?v=8PyqL9y7VZo

MAGNETISM + - + + REPEL ATTRACT + - + + ATTRACT The electrons in a magnet are all perfectly lined up so that there is a north pole and a south pole.

MAGNETISM 1. Created by moving electrons (electricity) 2. The closer the magnets get to each other, the stronger the force. 3. The earth is a giant magnet, that’s why a compass points “North” 4. Loadstone or magnetite is a natural magnetic mineral 5. The only things that are attracted to a magnet (besides other magnets)are iron, nickel, and cobalt. 6. Strongest part of the magnet=ends, where lines are closest

A force that holds atoms together! ELECTROMAGNETISM Watch both parts (A and B) https://www.youtube.com/watch?v=GMnsZuEE_m8 https://www.youtube.com/watch?v=cy6kba3A8vY A force that holds atoms together!

ELECTROMAGNETISM 1. Magnets can create an electric field. A force that holds atoms together! 1. Magnets can create an electric field. 2. An electric circuit can create a magnet.

ELECTROMAGNETISM 1. Magnets can create an electric field. A force that holds atoms together! 1. Magnets can create an electric field. Size of magnets # of magnets 2. An electric circuit can create a magnet. # of coils of wire around the nail Thickness of the nail Strength of the battery

STATIC ELECTRICITY Everything is made up of atoms. The parts of an atom are: Protons = Neutrons = Electrons = _______ ONLY electrons can move from one atom to the next…. A “build up” of electrons makes an object negatively charged A “shortage” of electrons makes an object positively charged When the charges build up enough and are stored in an object, the charge can jump quickly between two objects and it makes a shock!!

STATIC ELECTRICITY

STATIC ELECTRICITY

GRAVITY Any 2 objects are attracted to each other by gravity. The more mass the more attraction (gravity). The closer the objects, the more attraction (gravity). Gravity is different on every planet because the mass of every planet is different. It’s a force that pulls all objects towards the center of the earth.

GRAVITY