qz7sol_3891f10 - around a top. Then the string is pulled...

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TA: Tomoyuki Nakayama Tuesday, October 19, 2010 PHY 2048: Physic 1, Discussion Section 3891 Quiz 7 (Homework Set #8) Name: UFID: Formula sheets are not allowed. Calculators are allowed. Do not store equations in your calculator. You need to show all of your work for full credit. ________________________________________________________________________________ In the figure below, an irregularly shaped plastic plate with uniform thickness and density (mass per unit volume) is to be rotated around an axle that is perpendicular to the plate face and through point O. The rotational inertia of the plate about that axle is measured with the following method. A circular disk of mass 0.40 kg and radius 2.0 cm is glued to the plate, with its center aligned with point O (Figure b). A string is wrapped around the edge of the disk the way a string is wrapped
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Unformatted text preview: around a top. Then the string is pulled for 5.0 s. As a result, the disk and plate are rotated by a constant force of 0.60 N that is applied by the string tangentially to the edge of the disk. The resulting angular speed is 100 rad/s. a) What is the angular acceleration of the plate-disk system? Angular acceleration is the rate of change in angular velocity. We have = /t = 20 rad/s 2 b) What is the rotational inertia of the plate about the axle? Newtons 2 nd law yields I = = Fr I = Fr/ = 6 10-4 kgm 2 Since the system consists of the disk and the plate, the rotational inertia of the plate is I = I disk + I plate I plate = I (1/2)mr 2 = 5.2 10-4 kgm 2...
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This note was uploaded on 01/25/2011 for the course PHY 2048 taught by Professor Field during the Summer '08 term at University of Florida.

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