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Physics/founcault pendulum

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Question
Hi,

In foncault pendulum experiment, the pendulum that is hung is moving due to earth's rotation. Why normal pendulum which is hung with a shorter string is stationary.

Answer
It's named after a French physicist Léon Foucault, and is therefore spelled the same as his last name.  A normal pendulum is not free to swing along any axis, but constrained to swing by a simple hinge as the Earth rotates.  A Foucault pendulum is not, and the rotation of the plane in which it swings will depend on the rotation of the Earth.  Basically, the pendulum does not change the direction it swings as much as the Earth changes the direction under it in which it sits.  This effect is well-described (for thoroughness, perhaps not for clarity) in wikipedia, if you want full details of how the rotation depends on lattitude.  http://en.wikipedia.org/wiki/Foucault_pendulum

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Dr. Stephen O. Nelson

Expertise

I can answer most basic physics questions, physics questions about science fiction and everyday observations of physics, etc. I'm also usually good for science fair advice (I'm the regional science fair director). I do not answer homework problems. I will occasionally point out where a homework solution went wrong, though. I'm usually good at explaining odd observations that seem counterintuitive, energy science, nuclear physics, nuclear astrophysics, and alternative theories of physics are my specialties.

Experience

I was a physics professor at the University of Texas of the Permian Basin, research in nuclear technology and nuclear astrophysics. My travelling science show saw over 20,000 students of all ages. I taught physics, nuclear chemistry, radiation safety, vacuum technology, and answer tons of questions as I tour schools encouraging students to consider careers in science. I moved on to a non-academic job with more research just recently.

Education/Credentials
Ph. D. from Duke University in physics, research in nuclear astrophysics reactions, gamma-ray astronomy technology, and advanced nuclear reactors.

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