Ask-a-Physicist by Topic


Negative Mass

In general relativity, gravity is described as a distortion of space time. Most vulgarized books use the simplified image of a 2D plane being bent downwards by a mass, so that any matter traveling in the area would have to follow the bending of the plane, which would then explain why things are attracted to one another.

Keeping the same simplified metaphor, could we imagine something that would bend the plane upwards, thus causing objects to be repelled? Would such a thing be considered to have negative mass? Is the concept theoretically possible?

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Can particles have negative mass?

It looks like they are looking for positive mass particles at the LHC at CERN. Isn't it logical that there are negative-mass "anti-particles"? Does the LHC have the capability of measuring negative mass?

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Skydiving terminal velocity

I’m not a physics guy, but with all the discussion around the disaster in Oklahoma recently it had me pondering a terminal velocity question. From what I understand, any object with mass would possess a terminal velocity.

Since air has mass, what would be the terminal velocity of air? Specifically, how fast can a tornado/hurricane/natural disaster hurl air before it reaches a terminal velocity?

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Figure Skater Physics

In figure skating, if you are doing a spin on ice and you leave your arms spread out it creates resistance. If you pull the arms in toward the body, you create less resistance so you spin more easily. How do I express this with mathematical equations in physics?

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Falling Through the Earth

If somehow there was a tunnel straight through the center of the earth and we dropped a capsule through it, what will happen to the capsule? Would the tunnel shoot the capsule into space?

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Wave and Particle Duality

I have a question about waves and particles. Since waves and particles seem to be somewhat interchangeable at the subatomic level, at what wavelength does the wave / particle duality stop?

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Since the earthquake in Japan the country has been having trouble with their nuclear energy plants and possible meltdown. The question is why aren’t they using lead to absorb the radiation?

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What are the scientific reasons for spin or curve on a soccer ball? What forces are affecting this?

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weather Do you think humans will ever be able to predict the weather? BL, Schenectady, New York
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