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Re: [Phys-l] accelerated frames (was: pseudo force)



It may be useful to recall that kinematics from a wide class of "accelerated frames" is usefully analyzed into two different effects:

1) effects that arise from referring kinematical quantities to an ACCELERATING ORIGIN, and
2) effects that arise from referring kinematical quantities to a ROTATING COORDINATE SYSTEM anchored to the above accelerating origin.

I will refer to the combined effects 1) and 2) as effects referred to a "rotating/accelerating frame".

The acceleration of a particle as referred to a FIXED coordinate system, which is anchored to an INERTIAL origin, will differ from the acceleration of that particle as referred to the above rotating/accelerating frame by four terms:

a) the effect of 1) is simply to add Ao (the acceleration of the origin)
b) the effect of 2) is to add a Coriolis acceleration, a "transverse" acceleration, and a centripetal acceleration.

These 4 "inertial" accelerations must be added to the acceleration as referred to the rotating/accelerating frame in order to calculate the acceleration as referred to a fixed coordinate system anchored to an inertial frame. Quantitatively:

R'' = r'' + Ao + 2w x r' + w' x r + w x (w x r)

The notation should be apparent - consult Fowles' text for details (or ask).

Bob Sciamanda
Physics, Edinboro Univ of PA (Em)
http://www.winbeam.com/~trebor/
trebor@winbeam.com