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Unformatted text preview: A-PDF Split DEMO : Purchase from www.A-PDF.com to remove the watermark 2.2.1 Mechanics
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2j. . I I Fig. 2.2.11 Inertial reference (a) (b) Plane motion of a point mass: (a) physical; (b) circuit representation. node is represented by an arrow pointing toward the node. The extension of these representations to three-dimensional motion is straightforward. In order to obtain a representation for a mass element more general than a point mass, we need to review briefly the dynamics of rigid bodies. We consider first the translational motion of a rigid body. A rigid body, by definition, is one in which any line drawn in or on the body remains constant in length and all angles drawn in or on the body remain constant. In Fig. 2.2.12 we represent a rigid body with a mass density p (kilograms per cubic meter) that may vary from point to point in the body but remains constant in time at any point in the body. We define an inertial coordinate system (z, y, z) and specify the position vector r of an arbitrary point p that is fixed in the body. The instantaneous acceleration of the point p is
a, - d(r .. (2.2.12) dt Fig. 2.2.12 Geometry for analyzing the translation of a rigid body. _ ______ ...
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This note was uploaded on 02/10/2012 for the course MECE 4371 taught by Professor Liu during the Fall '11 term at University of Houston.
- Fall '11