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34 Cards in this Set
- Front
- Back
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A ___________ is any push or pull that causes an object to move, stop or change direction.
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force
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Three forces that affect objects on Earth are:
1 2 3 |
1. friction
2. magnetism 3. gravity |
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______________ is a force that opposes, or acts against, motion when two surfaces rub against each other.
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Friction
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___________ is the force of pushing or pulling between poles of magnets.
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Magnetism
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Every magnet has _________ poles.
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two
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________ is the force that pulls all objects in the universe toward one another.
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Gravitation
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The strength of the gravitation between two objects depends on the ____ of the objects and the _____ between the objects.
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mass
distance |
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The greater the distance between two objects, the ___ the force of gravitation acts on them.
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less
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What keeps the moon in orbit around the Earth?
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gravity
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When gravitation pulls a large and a small object toward each other, how are the two affected?
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The larger object will move less than the smaller object.
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Gravitation pulls objects towards the _____ of an object.
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center
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How does the Earth's magnetic field benefit us?
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It is strong enough to repel the most dangerous radiation moving through space.
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Two like magnetic poles will _____ each other.
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repel
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Two unlike magnetic poles will ____ each other.
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attract
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___ ____ are equal in size and opposite in direction.
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Balanced forces
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If you push against a cement wall, will that be a balanced force or an unbalanced force?
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balanced force
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If you push against a cart with wheels, will that be a balanced force or an unbalanced force?
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unbalanced force
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___ ____ occur when one force is greater than its opposite force.
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Unbalanced forces
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What causes acceleration?
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An unbalanced force
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What happens to an object's motion when unbalanced forces act on it?
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its motion changes
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When an object's motion has changed (speed up, slow down, move, stop or changes direction), it is called __.
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acceleration
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Forces always act in ____.
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pairs
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If you see a cat walk across a book shelf, hits a book and the book falls off the shelf, what are the forces at play here?
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cat, book
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If you see a woman pulling a grocery cart in Publix, what type of force is this?
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unbalanced force
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____ is the use of a force to move an object rhough a distance.
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work
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The metric unit of work is ___
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joule
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The formula to calculate work is _______ x_____ = work
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weight x distance = work
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The formula to calculate power is _______/ _____ = power
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work/time = power
(sec) |
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______ is the amount of work done for each unit of time.
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Power
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A ____ is something that makes work seem easier by changing the size or direction of a force.
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machine
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Name the six simple machines:
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1. pulley
2. lever 3. incline plane 4. wedge 5. screw 6. wheel and axle |
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(True/False) Pulleys reduce the amount of work to be done.
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False
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Name an everyday machine that uses a wheel and axle, and a set of wedges to cut.
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pen sharpener
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A ______ is a wedge at the end of a lever.
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shovel
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