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r34racer01
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A student sits on a freely turning stool and rotates with constant angular velocity w1. She pulls her arms in towards her body, and her angular velocity increases to w2.
In doing this her kinetic energy: increases, stays the same or decreases
I thought that since KE = 1/2Iw^2 that would mean an increase in w would be an increse in KE, but I hear otherwise, can someone clarify this for me?
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A boy of mass m = 50 kg running with speed v = 1 m/s jumps onto the outer edge of a merry-go-round of mass M = 100 kg and radius R = 2 m, as shown in the picture above. The merry-go-round is initially at rest, and can rotate about a frictionless pivot at its center. You may assume that the inital velocity of the boy is tangent to the edge of the merry-go round.
Which of the following quantities are conserved throughout this problem for the system consisting of the boy and the merry-go-round?
only kinetic energy
kinetic energy and angular momentum
only linear momentum
linear momentum and angular momentum
only angular momentum
I think linear & angular momentum are conserved because they are both conserved whether the collision is elastic or inelastic right?
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A gyroscope is turning such that in the picture the top of the wheel is coming out of the page and the bottom of the wheel is going into the page (the wheel is rotating in the sense of the curved arrow). The bar (which is attached to the center of mass of the wheel and of negligible mass) is being held up by a piece of string wrapped around its end.
Which direction does the angular momentum vector of the gyroscope point in?
+x
-x
+zThe direction of rotation (precession) of the gyroscope is:
counterclockwise in the plane of the page (rotating in the direction from the -x axis to the -y axis)
out of the page (rotating in the direction from the -x axis to the z axis)
into the page (rotating in the direction from the -x axis to the -z axis)
I am just completely lost on these 2. Can anyone break this down into simpler words?
In doing this her kinetic energy: increases, stays the same or decreases
I thought that since KE = 1/2Iw^2 that would mean an increase in w would be an increse in KE, but I hear otherwise, can someone clarify this for me?
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A boy of mass m = 50 kg running with speed v = 1 m/s jumps onto the outer edge of a merry-go-round of mass M = 100 kg and radius R = 2 m, as shown in the picture above. The merry-go-round is initially at rest, and can rotate about a frictionless pivot at its center. You may assume that the inital velocity of the boy is tangent to the edge of the merry-go round.
Which of the following quantities are conserved throughout this problem for the system consisting of the boy and the merry-go-round?
only kinetic energy
kinetic energy and angular momentum
only linear momentum
linear momentum and angular momentum
only angular momentum
I think linear & angular momentum are conserved because they are both conserved whether the collision is elastic or inelastic right?
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A gyroscope is turning such that in the picture the top of the wheel is coming out of the page and the bottom of the wheel is going into the page (the wheel is rotating in the sense of the curved arrow). The bar (which is attached to the center of mass of the wheel and of negligible mass) is being held up by a piece of string wrapped around its end.
Which direction does the angular momentum vector of the gyroscope point in?
+x
-x
+zThe direction of rotation (precession) of the gyroscope is:
counterclockwise in the plane of the page (rotating in the direction from the -x axis to the -y axis)
out of the page (rotating in the direction from the -x axis to the z axis)
into the page (rotating in the direction from the -x axis to the -z axis)
I am just completely lost on these 2. Can anyone break this down into simpler words?
Homework Statement
Homework Equations
The Attempt at a Solution
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