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42 Cards in this Set
- Front
- Back
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What is an object's change in position relative to a reference point?
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motion
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What are some ways we describe motion?
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direction, distance, and speed
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What is an object that stays (or appears to stay) in one place?
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reference point
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What is how fast something's moving?
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speed
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How can you calculate the average speed of something?
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distance/time
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What is the SI unit for speed?
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meters per second
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What is the speed of an object in a particular direction?
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velocity
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How do you determine resultant velocity?
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same direction-add
different direction-subtract the smaller number from the larger |
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What is the rate at which velocity changes?
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acceleration
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When does acceleration occur?
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When there's a change in speed, direction, or both
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When is acceleration positive and when is it negative?
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positive-increase in velocity
negative-decrease in velocity |
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How can you calculate average acceleration?
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final velocity-starting velocity/time it takes to change velocity
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How is it possible to be accelerating and traveling at a constant speed?
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if you change direction
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What is the acceleration that occurs in a circular motion?
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centripetal acceleration
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What is the push or pull on an object?
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force
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What can forces cause to happen to an object?
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changes in motion (stop, slow down, speed up)
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What is the unit used to measure force?
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Newtons (N)
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What is the combonation of all forces acting on an object?
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net force
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How do you calculate net force?
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same direction-add
differenct direction-subtract the smaller from the larger |
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What is it when objects are in control?
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mechanical force
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What is it when objects do not need to be in contact?
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field force
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Describe a balanced force.
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-net 0 N
-won't cause a change in motion |
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Describe an unbalanced force.
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-net force isn't 0 N
-a change in motion |
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Give some examples of balanced and unbalanced forces.
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balanced-light hanging on cieling, book on desk, bird's nest in a tree
unbalanced-soccer ball after kicked, teeter-totter in motion |
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What is the force that opposes motion between surfaces that are in contact?
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friction
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What is the force that opposes motion between surfaces that are in contact?
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friction
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The amount of friction depends on what factors?
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-roughness of surfaces
-amount of force pushing object together -mass of objects (surface area) |
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What kind of an effect can friction have on an object in motion?
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-slow down or stop motion
-build up heat |
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What is the friction between moving surfaces?
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kinetic friction
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What is the friction between objects that balances any opposing force so object does not move?
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static friction
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What are some ways friction is helpful?
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-help you walk
-write with pen or pencil -keep car on road |
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What are some ways friction is harmful?
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-wear holes in clothes
-erodes soil -wears out machine parts |
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What are some ways you can reduce friction?
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-smoothing surfaces
-using lubricants -change sliding friction to rolling |
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what are some ways you can increase friction?
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-rougher surfaces
-increase forces on surface |
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What is the force of attraction between objects due to their masses?
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gravity
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What is the measure of the gravitational force of an object?
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weight
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What is the measure of the amount of matter in an object?
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mass
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How is mass and weight different?
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weight can change from place to place, but mass doesn't
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What is it that states all objects in universe attract eachother through gravitational force?
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Law of Universal Gravitation
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What factors affect the amount of Gravitational force?
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1.mass of object
2.distance between objects |
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Why would your weight change, not your mass if you landed on another planet?
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mass never changes; you never get smaller or bigger, but gravity would be different, so your weight would too
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What is the measure of gravitational force?
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weight
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