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Frames of Reference |
A Frame of Reference is simply a coordinate system used to describe the universe from a particular observer’s point of view. Most often it is a rectangular Cartesian coordinate system with x, y, and z axes mutually perpendicular to one another in a right-handed fashion. The coordinate system is usually non-rotating and centered on the observer. And the observer’s clock is used as a basis for specifying the time t.
Although right-handed, non-rotating, rectangular Cartesian
coordinates are used most often, polar coordinates, rotating systems, and even
generalized coordinates are sometimes used as frames of reference. These unusual
coordinate systems are used whenever they simplify the situation or when
another viewpoint is desired. For example, spherical polar coordinates (r,q,f) are often used when spherical symmetry
is present, rotating coordinates are used in rotating situations (like the
rotating earth), and generalized coordinates are used when coordinate
independent conclusions are desired.
Quite often the term “frame of reference” is used in a very general sense without implying any particular observer or coordinate system. In this case, the term refers to a potential observer’s point of view independent of coordinate system. In essence, it allows any observer to take that viewpoint and leaves the observer free to utilize whatever coordinate system he desires. Nevertheless, the phrase “frame of reference” does imply that some observer will eventually choose some kind of coordinate system to describe the universe. After all, without an observer or a coordinate system, there really can be no “frame” and no “reference.”
Q1. Multiple Observers in Multiple Frames.
Which of the following
statements are true? (A) It is possible for a single
observer to utilize more than one frame of reference at the same time. (B) It is possible for different observers to utilize the same
frame of reference at the same time. (C) It is possible
for an observer to switch from one frame of reference to another. (D) More than one of these are true. (E)
None of these are true.
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