# Unit 2 Test Study Guide (Friction,Gravity and Newton’s 1)

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Why is it important to keep accurate records, notes and charts while doing an experiment?

So experiment can be repeated the same way again
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why is it easy to slip when there is water on the floor

there is less friction
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what factors impact the amount of friction between objects

the amount of force between the objects and the roughness of the surfaces
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a box being pushed across the floor (type of friction)

sliding
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a bird flying through the air air (type of friction)

sliding
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a book sitting on a table (type of friction)

static
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riding a skateboard (type of friction)

rolling
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which of following examples has the greatest amount of friction between the object

a box being pushed across the floor
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why must you exert a force to pick up an object ? what must you overcome

an object at rest tends to stay at rest you must overcome gravity
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Law of Universal Gravitation

Gravitational force increases as mass increases Gravitational force decreases as distance increases
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weight

measurement of how hard gravity is pulling on that object
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mass

amount of matter in an object does not change based on location
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if earths mass doubled without changing its size, what would happen to your weight

your weight will double because of the increase in gravitational force
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how would the gravitational force between 1kg of lead and earth compare to the gravitational force between 1kg of marshall and Earth

the gravitational force would be equal because the masses are equal
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a penny is dropped from the top of a tall stairwell. what is the penny's velocity after it has fallen for 4s

39.2
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terminal velocity

is the constant velocity of a falling object when the force of air resistance is equal in magnitude and opposite in direction to the force of gravity
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what is not projectile motion

swimming in a pool of water
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the acceleration of an object depends on the mass of the object and the amount of force applied

newton's 2
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whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first

newton's 3
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according to newton's 2 law how can you increase the acceleration of an object that is pushed by a force

reduce the mass or increase the force applied
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when you ride the bus, why do you fall forward if you are standing and the bus moving

when the bus stops your inertia hasn't been changed and you will continue in motion
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when a soccer ball is kicked, why don't the action and reaction forces cancel each other out