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Unformatted text preview: Brian Joseph Fuqua- PHGN100, Spring 2006 1 Test 2 Multiple Choice 10 point(s) A test tube filled with blood is spinning in a centrifuge. A platelet is pinned to the end of the test tube, a distance of 0.5 m from the axis of rotation for the centrifuge. As the centrifuge speeds up, the angular displacement for the platelet as a function of time is given by: θ ( t ) = bt 3 with b = 16 . 8 rad/s 3 and t the time elapsed since turning on the centrifuge. When t = 1.9 seconds, find each of the following: 5 pt The tangential component of acceleration: (in m/s^2 ) 1 . A 95.76 B 108.21 C 122.28 D 138.17 E 156.13 After the centrifuge is switched off, the test tube slows to a stop. The angular velocity of the platelet (still at the same radius) is given by: ω ( t ) = ω o e- t/t 2 with ω o = 181 . 9 rad/s, t 2 = 13 . 3 s, and t now the time since the centrifuge has been switched off. If the intitial time is the time when the centrifuge was switched off ( t i = 0), and the final time is t f = 11.7 seconds, find each of the following: 5 pt The angular displacement: (in rad ) 2 . A 464 B 673 C 976 D 1415 E 2052 5 pt 5 point(s) A yo-yo, arranged as shown, is at rest on a frictionless surface. F If a force is applied to the string as in the diagram, the yo-yo 3 . A moves to the left, rotating counter-clockwise B moves to the right, rotating clockwise C moves to the right, rotating counter-clockwise D moves to the left, rotating clockwise You are correct. Your receipt is 162-1756 10 point(s) Brian Joseph Fuqua- PHGN100, Spring 2006 2 Test 2 Multiple Choice θ A bob of mass 2.22 kg is hung from a spring with an unknown spring constant and is set moving in a horizontal circle as shown above. The rest length of the spring is 0.24 m, the spring length when bob is moving in the horizontal circle is 0.61 m, and θ = 30.4 degrees....
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This note was uploaded on 04/19/2008 for the course EGGN 389 taught by Professor Ammerman during the Spring '08 term at Mines.
- Spring '08