Ask-a-Physicist

Never-ending light in a room full of mirrors

If you had a light in a room which was entirely sealed with mirrors, then switched the light off, would the room stay lit?

Would the light just keep reflecting off the mirrors?

Would it slow down? Perhaps to the point where it is no longer visible?


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Basketballs, tennis balls, ping-pong balls, and physics

I understand what happens and why, when I drop a tennis ball that is resting on top of a basketball. What I am trying to figure out is, why do I not get the same results with a ping pong ball on top of a basket ball. Any ideas?


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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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Weight on Other Planets

If a person stepped on a home bathroom scale, and weighed 170 lbs, he would weigh a different weight on this same scale when on other planets due to the force of gravity.

If, however, a person stepped on a professional medical scale — the kind with weights attached that you slide (as opposed to a bathroom scale) and weighed 170 pounds on Earth, would the weight of the person be the same on the other planets as it is on Earth (170 lbs)? This has become a bone of contention in an otherwise ideal marriage.


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Infrared and Blackbody Radiation

Is there a particular range of frequencies at which parts of the human body (or the human body overall) normally vibrates? Because in an episode of the sci-fi TV series Fringe, they claimed that they could figure out if one character was from this universe or a parallel universe by measuring the frequency at which he was vibrating.


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