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Unformatted text preview: This print-out should have 13 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. 001 10.0 points A circular disk, a ring, and a square have the same mass M and width 2 r . disk 2 r ring 2 r square 2 r For the moment of inertia about their cen- ter of mass about an axis perpendicular to the plane of the paper, which statement concern- ing their moments of inertia is true? 1. I ring > I square > I disk 2. I ring > I disk > I square 3. I square > I disk > I ring 4. I square > I ring > I disk correct 5. I disk > I square > I ring 6. I disk > I ring > I square Explanation: In the ring, the same mass of the disk is concentrated at the maximum distance from the axis, so I ring > I disk . In the square, the same mass of the ring lies at distances which are between r and r √ 2 ( at least the radius of the ring), so I square > I ring and I square > I ring > I disk . 002 (part 1 of 2) 10.0 points Two particles move in opposite directions along a straight line. Particle 1 of mass m 1 = 25 kg at x 1 = 26 m moves with a speed v 1 = 28 m / s (to the right), while the particle 2 of mass m 2 = 47 kg at x 2 = − 20 m moves with a speed v 2 = − 36 m / s (to the left). Given: Counter-clockwise is the positive angular direction. d 1 m 1 m 2 x 2 x 1 v 1 v 2 d 2 A B x y What is the total angular momentum of the system about the z-axis relative to point A along y axis if d 1 = 17 m? Correct answer: 16864 kg m 2 / s. Explanation: The angular momentum along z axis is given by L = r p sin θ , where p is the total linear momentum. We find that p = m 1 v 1 + m 2 v 2 , where v 2 is negative. Since at point A r sin θ = − d 1 , we find l A = d 1 p = − d 1 (...
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