A torch on the end of a piece of string, in the centre of a cylinder, is spinning round at the speed of light. At what speed is the light from the torch hitting the inside wall of the cylinder, if light can not go faster than186,000mp/second. Surely, it would be travelling faster than this, if the point at which the torch was spinning was already travelling at the speed of light?
2007-02-01 00:27:37 · 7 answers · asked by Anonymous in Science & Mathematics ➔ Physics
The light hitting the cylinder is also traveling at the speed of light...If you had a stopwatch that could measure incredibly small fractions of time, you would find that when you started the experiment, no light had hit the inside of the cylinder yet. A small fraction of time later, the light would have finally traveled to the inside surface of the cylinder, and it would appear illuminated...
2007-02-01 00:37:25 · answer #1 · answered by BAM55 4 · 0⤊ 0⤋
The question has serious technical problems. First, the 'torch' is matter and not energy and can not be accelerated to the speed of light which would require infinite energy increasing its mass infinitely. Perhaps the torch approaches the speed of light (say 90%). Still light will travel in any direction from the tip of the torch at the speed of light which is a constant. The speed of light can be affected by concentrated mass. In a black hole a photon directed outward would stop and return (like a baseball on earth) due to gravity. It is a black hole because it emits no light and 'looks' like a black hole in space. Space has been distorted by the mass of the black hole.
2007-02-01 08:58:53 · answer #2 · answered by Kes 7 · 0⤊ 0⤋
You've described an impossible experiment. The torch can not be travelling at the speed of light, because to get to the speed of light, it would have to speed up from stationary. This would take an infinite amount of energy, and the torch would have an infinite mass, which would suck the entire experiment and the rest of the universe into a black hole.
2007-02-01 08:53:26 · answer #3 · answered by Gnomon 6 · 0⤊ 0⤋
It would still be travelling at speed of light.
These are the sort of questions that started Einstein thinking about light and time. If a car was travelling towards you and it shone a light at you wouldn't that light be travelling at the speed of light plus the speed of the car? No it isn't everything travels "relative" to the speed of light. Any extra energy e.g the speed of the car is used up by being converted into mass e=mc^2. A clever practical guy this Einstein fella.
2007-02-01 08:50:00 · answer #4 · answered by michaelduggan1940 2 · 0⤊ 0⤋
It is still traveling at the speed of light.
It's a real mind bender, has to do with the space/time continuum and it doesn't make sense with our understanding of frames of reference of time and space as we know it.
2007-02-01 08:37:15 · answer #5 · answered by Anonymous · 0⤊ 0⤋
five inches.
2007-02-01 08:37:20 · answer #6 · answered by peter p 5 · 0⤊ 0⤋
c.
2007-02-04 15:07:36 · answer #7 · answered by Anonymous · 0⤊ 0⤋