Physics/R E

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Question
Rotational energy is Joules

moment of inertia   X  angular velocity squared

kg m^2    x    rad^2  /  sec^2

Why aren't the radians cancelling ?

Answer
Common misconception.  Radians are a placeholder, and not a real unit.  They're a ratio of distance around a circle, divided by radius...so there's no unit left there when dist/dist cancels out.  The placeholder unit of radians can simply be dropped without error when real units are introduced.

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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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