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Force and Motion

Dive into the fascinating world of physics, where we explore the fundamental forces and motions that govern the universe. From the motion of planets and the structure of matter to the laws of inertia and gravity, we'll uncover how everything is interconnected. Discover how Newton’s laws shape our understanding of motion, learn about energy conservation, and see practical demonstrations that bring these concepts to life. Join us on a journey to understand the fundamental principles that drive everything in the universe, from galaxies to everyday objects.

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Force and Motion

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  1. Force and Motion

  2. What is Physics? • Study of the nature of the Universe • what the Universe is made of – Matter • stars and planets and galaxies • different forms like gases and liquids and solids • sub-atomic particles like protons and electrons • light and radiation • and how this ‘stuff’ behaves – Forces, Motion, Energy • how does a rocket get to outer space? • how can a bicycle stay upright on such thin tires? • how do protons and electrons make atoms, and atoms make molecules, etc? • how did the Universe as we know it come to be?

  3. What we do at Fermilab? • Study how the Universe works • accelerate protons to near speed of light and smash them into each other • see what happens in giant detectors • has anyone ever been to Fermilab?

  4. Newton’s Laws • Physics began a long time ago. . . • Why is Issac Newton famous? An apple fell on his head??

  5. Newton’s Law 1 – the glass/tablecloth • Newton discovered the rules of force and motion • objects at rest stay at rest; objects in motion stay in motion • “Inertia” = resistance to change in motion/rest • “Force” = something applied to overcome an object’s inertia and change its motion • push, pull • also gravity, magnets, electric charge glass & tablecloth

  6. Newton’s Law 2 • Newton discovered the rules of force and motion 2. F = ma the amount of force needed to speed up an object depends on how massive it is.

  7. Newtonian Demonstrator • pull back 1 ball • pull back two balls • one ball on each side • show works at any scale

  8. Momentum • moving objects have momentum • amount of momentum depends on mass and velocity • total momentumis always conserved • also can be transferred between objects

  9. Newtonian Demonstrator • what about replacing last ball with a smaller one? • conservation of momentum

  10. Gravity • Gravity is the pull of the Earth on all objects which makes them fall • actually, all massive objects pull on each other, but the masses are too small to notice

  11. Ramps & Skateboards • use ramps and skateboards to show that: • mass does not matter (force is larger, but so is inertia) • angle does matter (put heavier one on steeper board then on less steep board)

  12. Gravity doesn’t move moves faster G G moves slowly moves fastest G G

  13. Gravity mass doesn’t matter!! Galileo discovered that ~400 years ago air resistance: Moon hammer & feather video

  14. Rotational Motion / Rolling Objects • Moment of Inertia – resistance to change in rotation rate • two open cylinders (different mass) • open cylinder vs. solid bar (same mass) • solid bar vs. solid disk (same mass) • race all three • sphere is fastest • what about a hollow sphere vs. a solid sphere? It’s the Distribution of Mass that matters!!

  15. Figure Skater / Chair • this is exactly the principle that allows a figure skater to spin so fast and to change their speed of rotation • try it with a spinning chair, a student and a few small weights

  16. Angular Momentum • rotating obects have angular momentum • amount of momentum depends on location of mass and rate of rotation • total angular momentumis always conserved • also can be transferred between objects

  17. Bike Wheel / Lazy Susan • bike wheel remains vertical, precesses • transfer of angular momentum – student on the lazy susan with spinning bike tire

  18. Newton’s Law 3 – kids on skateboards • Newton discovered the rules of force and motion 3. for every action there is an equal and opposite reaction can show with 2 students on scateboards one pushes! then the other! can show with student and adult on scateboards

  19. Energy • everything has energy • total energyis always conserved • but can be transferred between different objects or different forms • potential energy • kinetic energy • heat energy • sound energy • electromagnetic energy • . . .

  20. Conservation of Energy Potential Energy Kinetic Energy Kinetic Energy Compression Energy Heat and Sound Energy

  21. Conservation of Energy • where does the energy come from to: • sail a sailboat? • make plants grow? • drive a car? • when a ball falls and speeds up? • cook toast? • . . .

  22. Pendulum PE -> KE -> PE

  23. What did we learn today? • Inertia • Moving things stay moving, stationary things stay stationary • unless you apply a force • Gravity • mass doesn’t matter – angle matters • Rotating objects are different • shape matters • Some things don’t change and that’s very useful for understanding • momentum, angular momentum, and energy

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