Chapter 4

Chapter 4 - Garland D. Jones Kinesiology Dr. W. Fordham M,...

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Garland D. Jones Kinesiology Dr. W. Fordham M, W, F 8:00-9:00 am Chapter 4: Biomechanics Chapter Terms: Acceleration: In physics or physical science, acceleration (symbol: a ) is defined as the rate of change (or derivative with respect to time) of velocity. It is thus a vector quantity with dimension length/time. In SI units, acceleration is measured in meters/second² using an accelerometer. Angular : an object with respect to a reference point is a measure for the extent to which, and the direction in which, the object rotates about the reference point.In particular, if the body rotates about an axis, then the angular momentum with respect to a point on the axis is related to the mass of the object, the velocity and the distance of the mass to the axis. Angular momentum is important in physics because it is a conserved quantity: a system's angular momentum stays constant unless an external torque acts on it. Torque is the rate at which angular momentum is transferred in or out of the system. When a rigid body rotates, its resistance to a change in its rotational motion is measured by its moment of inertia. Angular momentum is an important concept in both physics and engineering, with numerous applications. For example, the kinetic energy stored in a massive rotating object such as a flywheel is proportional to the square of the angular momentum. Conservation of angular momentum also explains many phenomena in sports and nature. Biomechanics : is the research and analysis of the mechanics of living organisms. The research and analysis can be carried forth on multiple levels, from the molecular, wherein biomaterials such as collagen and elastin are considered, all the way up to the tissue and organ level. Some simple applications of Newtonian mechanics can supply correct approximations on each level, but precise details demand the use of continuum mechanics. Center of mass : a system of particles is a specific point at which, for many purposes, the system's mass behaves as if it were concentrated. The center of mass is a function only of the positions and masses of the particles that comprise the system. In the case of a rigid body, the position of its center of mass is fixed in relation to the object (but not necessarily in contact with it). In the case of a loose distribution of masses in free space, such as shot from a shotgun, the position of the center of mass is a point in space among them that may not correspond to the
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position of any individual mass. In the context of a uniform gravitational field, the center of mass is sometimes called the center of gravity. Deterministic models
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This note was uploaded on 03/08/2011 for the course STA 4406 taught by Professor Mckinney during the Spring '11 term at FIU.

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Chapter 4 - Garland D. Jones Kinesiology Dr. W. Fordham M,...

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