The confusion of a rigid body.

[holocene]

If you place a pencil on top of a desk, and push one end of the pencil, doesn't the other end move INSTANTANOUSLY, and thus is infinitely faster than light?<br />

 

[yevaud]

No. There is a propagation time as the force you exert at one end of the pencil travels to the other end. You won't know it (too fast for you to see, to short a distance), but it's there. <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[why06]

that's true... This is called the speed of sound.<br />It is the speed at wich motion travels through a median. <br /><br />The speed of sound seems instantaneous also at close range, but at longer distances you can see and hear the the differance in time. knock on a longhand rail and see how long it takes the vibration to get to the other end.... <img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> <div>________________________________________ <br /></div><div><ul><li><font color="#008000"><em>your move...</em></font></li></ul></div> </div>

 

[vogon13]

And, believe it or not, in the 2 years I have been here, we have had any number of folks from the 'woo-woo' crowd, pontificate endlessly on relativity, quantum mechanics, and cosmological expansion, while they remained blissfully unaware that a disturbance passing through a solid does so at the speed of sound for that material.<br /><br />Seriously, folks fuzzy on the concepts of sound, need to reflect for a moment before holding court on photon anomalies . . . .<br /><br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>