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45 Cards in this Set
- Front
- Back
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What is a force?
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A push or pull
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When describing a force, what are three things that I must give?
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an amount, a unit, and a direction
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What units do I use for force?
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Newtons
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What are some examples of different types of forces?
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gravity; momentum
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What is meant by the term "net force"?
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Overall force acting on an object
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What does it mean to say that the net forces on an object are balanced?
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equal weight on each side
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What does it mean to say that the net forces on an object are unbalanced?
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unequal weight on each side
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Calculate net force on blocks as pictured on study guide.
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See study guide
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What is inertia?
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a property of matter by which it remains at rest or in uniform motion in the same place unless touched by an outside force
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What determines the amount of inertia of an object?
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gravity
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What is Newton's First Law of Motion?
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An object will remain at rest until an outside force acts upon it.
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What is the mathematical equation for force?
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f = m x a
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What factors affect the strength of gravitational attraction?
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mass and friction
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Why do astronauts float in space? Why do planets orbit the sun?
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because the pull of the earth is faint on the moon. Also because the sun has a gravitational pull on the planets.
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What is the difference between mass and weight?
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mass: how much matter is in an object
weight: how strong the gravitational pull pulls the object |
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What will the mass of an 85 kg astronaut be on the moon?
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not answered in study guide
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What units do I use for mass? For weight?
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for mass: grams
for weight: Newtons |
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What is the forumula used to calculate weight?
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W = m x g
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What is the acceleration due to gravity on Earth?
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terminal velocity
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What is air resistance?
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resistance of an object to gravity while falling
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What two factors affect the amount of air resistance on an object?
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velocity
cross-sectional area |
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How do I calculate air resistance (think about the parachute lab)?
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velocity and speed act in opposite direction of an object's motion
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What is meant by the term "terminal velocity"?
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final speed
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Why does an ojbect reach terminal velocity?
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because the object has to stop someplace
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How do parachutes work?
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they use air resistance and take up as much space as possible while having a small weight
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What is friction?
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a foce that opposes motion between two touching surfaces
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What are the three types of friction?
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sliding
rolling fluid |
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What does the coefficient of friction tell us?
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not answered in study guide
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What is Newton's Third Law of Motion?
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for every action there is an equal and opposite reaction
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Does the Third Law mean that all forces are balanced? Why or why not?
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yes, because there is an opposite reaction for every action
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How do rockets work?
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they use newton's third law: the hot gas is the action, causint it to shoot forward, which is the reaction
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What is momentum?
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when an ojbect picks up speed
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How do we calculate momentum?
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p = m x v
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What units do we use for momentum?
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m/s
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What does the Law of Conservation of Momentum state?
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nothing changes unles there is an outside force
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What does Newton's Law of Universal Gravitation state?
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most objects in th euniverse are too small to have a gravitational pull
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Make sure you know how to calculate all problems in study guide (items 39-47)
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See study guide
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What is formula for Speed/Velocity?
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s = v = d / t
d = s x t t = d / s |
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What is formula for acceleration?
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a = (vf - vi) / t
t = (vf - vi ) / a vf = (a x t) + vi |
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What is formula for force?
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F = m x a
a = F / m m = F / a |
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What is formula for momentum?
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p = m x v
v = p / m m = p / v |
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What is formula for weight?
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W = m x g
g = W / m m = W / g g = 9.8 m/s squared on Earth |
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What is gravity on Earth?
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9.8 m/s squared
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what is the weight of a 5 gram pencil on earth?
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5 grams
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What is Newton's Second Law of Motion?
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The acceleration of an object is related to the net force acting on it and the mass of the object
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