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30 Cards in this Set
- Front
- Back
What is the difference between something that is rotating and something that is revolving?
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An object that is rotating is moving around an axis that is inside or internal to the object.
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You and your friend are side-by-side on a carousel. Which has the greater LINEAR speed
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the carousel horse on the inside or the carousel horse on the outside? Why?
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You and your friend are side-by-side on a carousel. Which has the greater ROTATIONAL speed
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the carousel horse on the inside or the carousel horse on the outside? Why?
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Why is an object going in a circle always accelerating?
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An object going in a circle is always accelerating because it is constantly changing direction.
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What is the meaning of the word “centripetal”?
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Center-seeking
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If an object is moving in circular motion and the centripetal force is removed
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describe the new motion of the object.
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A kid is revolving at a steady speed on a sit-n-spin. In what direction is he turning?
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Inward towards the center of the circle.
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A kid is revolving at a steady speed on a sit-n-spin. What is the direction of his centripetal acceleration?
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Inward towards the center of the circle.
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A kid is revolving at a steady speed on a sit-n-spin. What is the direction of his centripetal force?
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Inward towards the center of the circle.
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Why don’t you fall out of roller coasters when you are upside down at the top of a loop? (Hint
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you don’t need seatbelts or other mechanical restraints to keep you in.)
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What is providing the centripetal force on the clothes spinning in a clothing dryer?
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The walls of the dryer provide the centripetal force making the clothes go in a circle.
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What is providing the centripetal force on a rock attached to a string being whirled above your head?
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The string provides the centripetal force making the rock go in a circle.
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What is providing the centripetal force on a Match Box car going through a circular loop in its track?
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The track provides the centripetal force making the car move in a circle.
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Explain how two kids tossing a ball on a merry-go-round might see a fictitious force.
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In the time it takes for the ball to move across the merry-go-round the spinning motion has caused the kids to change their position. So the kids see the ball appear to curve when it is actually moving straight in a fixed reference frame.
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Explain how you could use rotation to simulate gravity in space.
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Spin a large wheel shaped space station so that people’s inertia makes them feel as though they were being pushed outward and that simulates the experience of gravity on Earth.
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A bug is on a record player. If the bug walks from the center of the record towards the outside edge of the record what would happen to its LINEAR VELOCITY?
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The bug's linear velocity would INCREASE because it would travel a greater distance around the record in the same amount of time.
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A bug is on a record player. If the bug walks from the center of the record towards the outside edge of the record what would happen to its ROTATIONAL VELOCITY?
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The bug's rotational velocity would STAY THE SAME because it would make the same number of rotations in the same amount of time.
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Why is a wrestler more stable when his feet placed far apart?
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He has a bigger base of support makes it easier to keep his COG over it.
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Why is a wrestler more stable when his knees are bent?
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It lowers his COG and makes it harder to topple over.
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What is the definition of this term: Axis
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The line an object turns around
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What is the definition of this term: Rotation
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When an object turns around an external axis
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What is the definition of this term: Revolution
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When an object turns around an internal axis
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What is the definition of this term: Linear Speed
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Speed in a straight line – distance/time
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What is the definition of this term: Rotational Speed
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Rate of rotation - # of rotations/time
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What is the definition of this term: Centripetal Force
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Only real force in circular motion – directed inward
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What is the definition of this term: Centrifugal Force
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NOT A FORCE – a sensation due to an objects inertia
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What is the definition of this term: Center of Gravity
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Center of an objects mass distribution
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What is the definition of this term: Stable Equilibrium
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When any movement will raise an object’s COG – must do work to lift
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What is the definition of this term: Unstable Equilibrium
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When any movement will lower an object’s COG
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What is the definition of this term: Neutral Equilibrium
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When movement doesn’t change the height of an object’s COG
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