Unformatted text preview: Physics 7B S10 Quiz 6 Last Grade: Student ID: Name: , Sec #: First 1) (40%) A thin rod rotates about its center as depicted in the diagram. Each of the 4 forces applied to it might contribute to the torque. Rank the magnitudes of the torques τA, τB, τC, τD. A B C ϑ 2) Our astronaut has goUen stuck in space again while trying to repair the shuUle’s wheel. This Yme, both the wheel and the astronaut are staYonary. While the astronaut clearly failed to learn how to stay aUached to the shuUle, he did at least learn more about linear momentum, so he throws the wheel to the le[ in an aUempt to return to the shuUle. However, when he throws the wheel, it begins to spin. D Imagine the astronaut to be represented by the diagram in problem 1, but without any of those forces acYng on it. Treat the astronaut (m=100kg) as a thin rod (I=m L2/12, same shape as the diagram of problem 1) of length 1.8m. Treat the wheel (m= 35kg, r=0.3m) as a solid disk (I=m r2 / 2). A[er being thrown, the wheel is spinning with an angular velocity of ω=0.7 rad / s (in to the page). A) (30%) Draw an angular momentum chart for the astronaut and the wheel. B) (30%) What is the angular velocity of the astronaut a[er he throws the wheel? Is he rotaYng clockwise or counter
clockwise? Useful EquaYons: L = I ω; L=r p sin θ; p = m v; τ=r F sinθ; ω=v / r ...
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This note was uploaded on 01/05/2011 for the course PHY 7B PHY7B taught by Professor Cebra during the Spring '10 term at UC Davis.
 Spring '10
 Cebra

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