Clarify maximum speed, plz. (eg: speed of c )

[waxy]

Picture a person holding a rod that is infinantly long.<br />The person spins so that a point on the rod 10 feet from the <br />piviot point travels a distance of 1 mile in 1 hour.<br /><br />if the rod were 100 light years long, would not a point on <br />the tip of that rod travel more than 186,282 miles a <br />second?<br /><br /><br />

 

[mlorrey]

If it were 100 ly long, you would never be able to accelerate it to that speed. An infinitely long rod will be the proverbial immovable object, given that with infinite length, even the slightest torque upon it would tranlsated into attempted superluminal acceleration at a finite distance along the rod. For instance, a rod that is 59205.638830185064906024759974575 miles long cannot be spun as fast as 1 rotation per second, else its tips will reach light speed.<br /><br />If your rod is a laser beam emitted from a pointer pen, you can spin it because the light is massless and the fact that photons emitted by the pointer are mechanically detached from the pointer at the moment they leave the laser. A spot from a laser beam shifting across a cloud of interstellar gas faster than c is not violating c, because the spot is not moving, only the interception point of the photons emitted by the pointer as the pointer shifts orientation.

 

[waxy]

<i>"For instance, a rod that is 59205.638830185064906024759974575 miles long cannot be spun as fast as 1 rotation per second, else its tips will reach light speed. "</i><br /><br />but saying that it can't because it breaks our <br />understanding does not explain why it can't. that <br />statement mearly explains the limit of our understanding.<br /><br />to say "Because as an object increses in speed it also<br /> increases in mass", as i'm sure someone will point out<br />when they read this, does not explain WHY it would <br />increase in mass. Mass is the ammount of matter in a <br />specified volume. to say something increases in mass is<br />to say it also increases in matter - or that the same matter<br />consumes less required volume.<br /><br />Likewise - how long does it take for force to travel across <br />composed matter? if you take the same rod, give it a <br />distance of 186,282 from center to the end, and then<br />'push' it at the center, the ends will move in unison with <br />the center. The force of this push may not be matter, but<br />it is not infinante mass, this force will move the ends at <br />the same speed it moves the center regardless of the fact <br />that the force must travel down the length of the rod <br />through the atomic bonds.<br /><br />I appericiate your paitence with my inqury.<br /><br /> [edit] bbcode error [/edit]

 

[siarad]

Surely as there's no movement of the centre the law isn't broken. The rod isn't <i>going</i> anywhere.

 

[nacnud]

<font color="yellow">Likewise - how long does it take for force to travel across<br />composed matter?<br /><br /><font color="white">Force in this case is transmitted from atom to atom via electromagnetic forces. These travle at a speed determind via the permittivity and permeability of the medium through which they travle. These also defince the speed of light.<br /><br />So the maximum speed the force can be transmitted is the speed of light.</font></font>

 

[chew_on_this]

Maybe this person is here to learn. Perish the thought!

 

[CalliArcale]

Agreed.<br /><br />The day we ban the asking of questions is the day I resign and leave this place, quite honestly. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[mlorrey]

Pushing is different from spinning. Spinning is imparting an angular velocity that translates at increasing distance along the rod into increases in mass of those portions of the rod. For any given rod length, there is an angular velocity at which you can spin the rod which causes the ends to go so fast as to attain nearly infinite mass, requiring similarly large amounts of energy to accelerate any further. If you are limited to 1 million horsepower, approximately 749,000,000 watts, there is a set angular velocity that you can spin the rod in a perfect vacuum and no faster. There are similarly finite rpm limits for every finite amount of power.<br /><br />The reason this happens is because, by the electromagnetic forces mechanically linking the atoms at the axis with the atoms at the tips, you are leveraging the velocity limitations of light speed to quite local and mundane human velocities, like a huge speed reduction gear.<br /><br />That being said, if Bussard ramjets become technologically feasible, you could build a ramjet powered, hydrogen fuelled power generator with the generator at the center and two ramjets at either end.<br /><br />Those of us with large power needs who do not want to use up all the water on planet Earth, or pollute it all with solar panels, for environmental reasons (Beware Peak Water) in fusion power plants may consider this a truly low impact power source...

 

[waxy]

<i>"Again, more of these ignorant claims, which have no scientific basis, and once again, as we've written before, show the dreadful ignorance of Americans regarding basic, physics 101. </i><br />defeat ingnorance through education rather than complaining.

 

[silylene old]

Steve, in this case, since the thread title is a question and a seeking of information and eductaion <font color="yellow">"Clarify maximum speed, plz. (eg: speed of c )"</font> I thought this was an entirely appropriate thread. He then posed a question which was clearly provoking his curiosity.<br /><br />If waxy had instead posted under the title "science is wrong and evidence proves speed of light is not constant", then his thread should be moved to Phenomena (or worse). But he didn't. I have no objection to people trying to learn with an open mind. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[abhinavkumar_iitr05]

Dear Waxy,<br /><br />Your question in a layman language is an excellent one.But while concerning with any thing related to speed of light we should have to be very careful.We can't ignore the THEORY OF RELATIVITY.While considering the particle at far of place we should not forget that time,mass & length all depend on the the speed according to the Special Relativity.<br />Its true that <br /><br />Speed = Distance/Time<br /><br />But while calculating the speed of the far of particle we should also have to take into the account the variation of time with speed.<br />According to the Relativity concept we have <br /><br />Time at speed v = Time at rest multiplied by square root of (1-v^2/c^2).<br /><br />Now as we approach speed of light flow of time becomes slower & slower.Thus applying the formula we have to keep the time calculated from the above formula.<br /><br />One more thing I would like to tell is that we will not be able to rotate the rod with that speed because mass of the rod increases with speed according to the following fprmula<br /><br />Mass at speed v=Rest mass divided by square root of (1-v^2/c^2).<br /><br />For more detail read Special Theory of Relativity.

 

[waxy]

Oh, abhinavkumar_iitr05, i was so pleased to see someone go in <br />depth with explaining the answer. it's also nice to see the <br />formulas.<br /><br /><i>"For more detail read Special Theory of Relativity."</i><br />book, link, or einstein's paper? can't afford a book (yeah, even<br />a mere $5 is a small fortune to me) but i'd appericate a juicy <br />link if you have one. (in the mean time i'll be google-ing)<br /><br />Your answer inclines me to understand that while the object or<br />segment along the example rod is indeed increasing in speed, <br />it's hyperbolic in that increase and appears so because as time<br />slows down for that segment of the example rod then the observed<br />speed is hyperbolic also - it'd take longer to move by our perspective <br />while infact it doesn't - it just seems so because it's in a diffrent<br />state of time passage. Am i getting a grasp?<br /><br />one immeadiate question i have, however, is about this:<br />Mass at speed v=Rest mass divided by square root of (1-v^2/c^2).<br />If i understand my pathatic education, then speed is relevant<br />(eg: am i falling toward the ground or is the ground jumping toward me)<br />if that is so, then how can mass at speed v not be relevant? <br />(bending space???)<br />also, my understanding from that formula is that as something<br />approaches the speed of light, then it's mass increases.<br />My understanding of mass is that it's matter to volume ratio.<br />So is there more matter coming into exsistance somewhere or<br />is the volume shrinking? <br /><br />Volume shrinking: if it's caused by einstein's bending space, then wouldn't any ruler measuring that matter also be <br />bending and thus measure the same matter/volume ratio <br />causing it to display the same mass.... ?<br /><br />Trying to get a grip. thanks for the community's paitence.