# Forces

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## Forces

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##### Presentation Transcript

3. Word Bank 1. Force – a push or a pull that makes an object move, slow down, stop or change direction 2. Friction – a force that stops a moving object when two objects are rubbed together; can cause heat 3. Magnetism – a force that has an attraction to magnets or magnetic objects

4. 4. Gravitation – a force that pulls all objects toward the center of the Earth. 5. Balanced Forces- When 2 objects have enough force to balance each other; opposite directions; no movement 6. Unbalanced forces – 2 forces that are in opposite directions; one force is greater than the other and the object moves in that direction.

5. 7. Position- an object’s place or location 8. Speed- a certain distance traveled in a specific amount of time Example: 79 miles / hour (mph) 16 meters / second (m/s) 9. Energy – a change in matter

6. 10. Kinetic nrg – nrg of motion; moving nrg 11. Potential nrg – nrg that is stored 12. Law of conservation of nrg – nrg cannot be created or destroyed; always the same amount of nrg present.

7. 13. Thermal nrg – when molecules of matter move; type of kinetic nrg 14. Electric nrg – movement of electrons; type of kinetic nrg 15. Light energy – nrg that moves in waves; type of kinetic nrg 16. Sound nrg – nrg that moves through vibrations; type of kinetic energy

8. 17. Transformation of nrg – when nrg is changed from one form to another

9. What I Know • Force is a push or a pull. • Magnets – opposite poles attract (pull together) alike poles repel (push away/ apart) 3. 3 kinds of everyday forces are – • Gravity • Magnetism • Friction

10. 4. Gravity tries to pull all objects to the center of the Earth. 5. Balanced forces have 2 forces pushing or pulling in opposite directions = no movement (balance each other) 6. Unbalanced forces have 2 forces pushing or pulling in opposite directions = movement in the direction of the stronger force.

11. 7. All objects fall at the same speed unless there is air resistance present. (Example: sheet of paper falling vs. a student dictionary dropping.). 8. Formula for Speed: Distance / Time = Average Speed 9. Motion is a change in position.

12. 10. A person’s Frame of Reference is how they observe a particular object’s motion. (This is the person’s point of view) 11. Kinetic nrg has many forms - 1. mechanical nrg 2. thermal nrg 3. light nrg 4. electric nrg 5. sound nrg

13. 12. Potential nrg has many forms – 1. elastic potential nrg Ex: rubber bands, silly bands, slinky, bed springs 2. gravitational potential nrg Ex: water behind a dam, pencil dropping, ball bouncing