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http://xkcd.com/332/
It *is* kinda freaky...
"You spin me right round, baby, right round, in a mannar which robs me
of an intertial frame of reference... baby..."
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> "You spin me right round, baby, right round, in a mannar which robs me
> of an intertial frame of reference... baby..."
It'd be fun to build a clock that ran off a gyroscope measuring the
movement of the earth.
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Tim Attwood wrote:
> It'd be fun to build a clock that ran off a gyroscope measuring the
> movement of the earth.
http://en.wikipedia.org/wiki/Foucault_pendulum
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Tim Attwood schrieb:
> It'd be fun to build a clock that ran off a gyroscope measuring the
> movement of the earth.
"It was Foucault who gave the device its modern name, in an experiment
to see (Greek skopeein, to see) the Earth's rotation (Greek gyros,
circle or rotation), although the experiment was unsuccessful due to
friction, which effectively limited each trial to 8 to 10 minutes, too
short a time to observe significant movement."
It'd be fun to build a gyroscope device measuring spacetime curvature
and frame-dragging....
http://en.wikipedia.org/wiki/Gravity_Probe_B
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Invisible schrieb:
>
>> It'd be fun to build a clock that ran off a gyroscope measuring the
>> movement of the earth.
>
> http://en.wikipedia.org/wiki/Foucault_pendulum
... which, by the way, constitutes a "vibrating structure gyroscope".
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Invisible wrote:
> http://xkcd.com/332/
Random question: A gyroscope works because it is [apparently] impossible
to turn the axis of rotation of a rapidly spinning object. So how come
cars can go around corners?
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Invisible schrieb:
> Random question: A gyroscope works because it is [apparently] impossible
> to turn the axis of rotation of a rapidly spinning object. So how come
> cars can go around corners?
Because that's actually /not/ why a gyroscope works :-)
The gyroscope works because angular momentum in a closed system must be
constant. Angular momentum is a vector, and as long as the gyroscope is
undisturbed, this vector is parallel to the axis of rotation.
What happens when you (comparatively slowly) rotate a rapidly spinning
object's axis is that as the object's angular momentum vector changes,
it will exert a torque force on its bearings that will impart this
difference in angular momentum unto the "outside world". (As a matter of
fact, this torque force does not even oppose the turning of the axis,
but acts perpendicular to it instead.)
The trick with a gyroscope is that the suspension is designed in such a
way that (a) the rapidly spinning object itself is subject to as few
rotational movement as possible in the first place, and (b) that it
cannot impart any angular momentum unto the "outside world". Instead,
the torque force will just cause another turning of the gyroscope's
axis, which again will result in a torque force, now countering the
initial disturbance.
In contrast, when you steer a car around a corner, the resulting effect
is that you just slightly change the angular momentum of the earth, to
compensate for any rotating parts' (motor, wheels etc.) change in agular
momentum.
You can experience the effects, however, when riding a bicycle "without
hands": If you are going fast enough and lean sideways so that the bike
will tilt, the front wheel will automatically turn in that direction
(even though most front wheel suspensions are actually designed in such
a way that gravitation alone would turn the wheel to the opposite side
instead).
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