If your moving faster than the speed of sound?
930735
Is the person next to you moving at the same speed as you?  If so you'll hear him fine.  If he's not moving at all then you'll never hear him, as the sound can't catch up to you.\n\nImagine another scenario to understand what I mean.  You're on an airplane which is stationary (say it's parked at the loading gate) and you're running down the corridor of the plane.  You can reach a maximum speed of 30 km/h.  Now, if the plane is moving at 300 km/h and you're running up the corridor, you're moving effectively at 330 km/h.  It's the same with the sound coming from your mouth.  If you're moving at a speed of X, when the sound comes out of your mouth, it's moving at a speed of X + roughly 350 m/s (the speed of sound).
56541
You would be in a different universe than you are now, because the laws of our universe say that a massive object can't go faster than the speed of light (or even as fast).\n\nAlso, if you changed the question to "...1 mile per hour less than the speed of light", you would have to specify "relative to ..." (what?)  And then you would have to say, what would happen as observed by (whom?).  In this question, relative to you, the headlights would turn on and you would be able to see things 186,000 miles ahead of you (as you measure miles) within 1 second (as you measured seconds) .  Relative to the observer that thought you were moving 1 mile per hour less than the speed of light - assuming you were moving toward the observer - you would get to him or her just a tiny fraction of a second after he/she saw the headlights turned on.  Your measurement of the speed of light would be consistent, but your measurments of time and distance would be very different.
409498
By traveling faster than the speed of light.  As velocity approaches the speed of light, time slows down.  Traveling faster than light speed then - would make you travel back in time.  Theoretically, it is possible (according to the theory of relativity) but scientifically, it doesn't seem possible.
399954
SPEED=dy/dt=distance/time.its not exactly something you invent.it was an axiom,a basis of understanding.
741475
Good question.\nNo. If you are travelling faster than the speed of sound (faster than Mach 1), you can not hear an echo of the sounds that you make.\n\nIn order to hear an echo, the sound must travel from your location, bounce off something, and return to you. \n\nIf you are travelling faster than Mach 1, all of the sound that you make is behind you. Whether it bounces or not, it can not come back to you, because once it's behind you it can't catch up with you.\n\nHere's an interesting thought: \nIf you subsequently slow down to less than Mach 1, then the sounds that you made while travelling faster than Mach 1 will start catching up with you. When you hear those sounds, they will not be echos in the sense of "sound that BOUNCED back to you." But you would experience the same effect as an echo (a sound that emanated from you, and later reached your ears).
140476
Speed and direction, if thats what you're asking
32072
Values of the Speed of Sound:\n\nOne of the most common questions we receive is fow fast is the speed of sound, and as was pointed out earlier, there is no single value to quote. The speed of sound, also known as Mach 1, changes throughout the atmosphere based on the temperature at any given altitude. Probably the most important value to remember, however, is the speed of sound at sea level. Based on the standard atmospheric model, this value has been defined to be\n\n    * 1,116.4 ft/s\n    * 340.3 m/s\n    * 761.2 mph\n    * 1,225.1 km/h\n    * 661.5 knots\n\nIf you were to reach Mach 1, or "break the sound barrier," at sea level, the above speed is how fast you would have to travel in order to do so.
30733
If you were traveling at the speed of light, whether or not your lights work would probably be the least of your concerns.\n\nIn reality, the laws of physics prevent any object from traveling faster than the speed of light.\n\nSomething that is perhaps just as interesting, however, is what happens as your vehicle APPROACHES the speed of light.  Take a look at some of the work done by Einstein to get a general idea on that.
317297
Yes, you would be able to hear it fine.  The radio waves travel at the speed of light.  This is many thousands of times faster than the speed of sound in air.  Your radio would be wholly unaffected in any way.\n\nYou would not, however, be able to hear a direct sound from someone talking to you and standing still.  The sound waves from their mouth are travelling at the speed of sound.  But the information carried by radio waves is not converted into sound waves until it gets to your receiver.
1019637
yes sound does travel faster in denser mediums, but when the temperature of a medium drops, then the viscosity of the medium drops as well, then even though the density would get higher, the sound would still slow down, because of the now less viscous medium.\na hotter medium would be more viscous then a cold one, therefore, sound travels faster in hot water, then it does in cold water
328292
Yes, the radio is also going to be traveling at the speed of sound because it is in the car or whatever you are in. Therefore the radio is stationary relative to you, so it makes no difference how fast you are going. If you were going away from the radio you would not be able to hear it.
588418
No....your breathing rate doesn't jump that fast...and if you've been running for a while, you'll be exhaling as fast as you inhale....
174761
nop i dont think so ...bcs our body wont handel thats speed
204850
yes ... unless you manage to move in a certain direction at a very accurately calculated certain speed.
776937
Just move yr legs faster.
118955
yes faster than I can say it forwards\n\n\nzyxwvutsrqponmlkjihgfedcba
792607
0 km/hr^2 .... because your speed doesn't change with time due to constant as you mentioned