Somenath,
i've looked a a few textbooks on fluid dynamics. they give the same argument:
a fixed volume goes faster in a narrower tube region than in a wider.
the acceleration required comes from a force along the axis of the pipe.
this is why, in my example of the constant diameter tube...
alas, i still haven't made myself clear.
in the hypodermic syringe structure, the piston in the smaller tube is moving faster than the piston in the larger tube. they are moving in the same direction at speeds that keep the VOLUME CONSTANT.
in an ideal liquid there is a smooth velocity vector...
Aero51,
i think of a piston as a disk with a rod attached, as in a hypodermic needle or a bicycle pump. in the (constant diameter) tube, the left hand piston has its rod pointing to the left, then there is a space for the liquid or gas, and then there is the right hand piston with its rod...
let's think of a simpler situation:a (horizontal) tube with 2 pistons,the cylindrical volume filled with an ideal liquid. keep the pistons stationary with horizontal pressure as necessary.
case#1:tube stationary.
case#2:tube accelerating (to the left, say).
case#3:tube moving at a constant...
perhaps i should have asked why a gas can be seen as having a "flow".
does that mean the substance has streamlines?
am i the only one confused by this?
thanks for responding.
i'm still (pardon me) up in the air on this.
if i understand what quasi-static means, then the speed of the pistons doesn't matter for a gas: the pressure is the same throughout.
on the other hand, the gas is treated as a liquid, and hence the Bernoulli equation applies...
it's been a while since i posed the question, but no response. is the question too easy or too hard?
in my physics textbook, ideal gasses are treated separately from ideal liquids.
yet, when an airplane wing is discussed, the air is treated as a liquid.
consider a hypodermic needle like structure with a piston in the larger tube and a piston in the smaller tube as well.
let the cavity be filled with an ideal incompressible fluid.
if i understand the Bernoulli theorem correctly, if a pressure is applied to the larger piston, causing the fluid...
In the equation there is an (r cross (v cross a)) term (script r in the text) where:
r=vector from a point charge q to a test charge Q,
v=velocity vector of q,
a=acceleration vector of q.
For each q on the rotating ring, v cross a is a vector parallel to the z axis. Put Q on the x-axis far...
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even though the negative charge is accalerating toward the center of the loop, and the velocity vector cross the acceleration vector is non-
zero?
p.s. as i am not a physics person, would you include the definitions of terms, so i can look them up?
p.p.s. i don't think the question i trivial...