If I were riding my motorbike, at say 50 kph, and then at a particular point shouted out my name, theoretically speaking, would my voice reach a person standing, say 50 m ahead, at the same time as it would as if I were standing at that same point and shouting?
In other words, would the sound waves be affected by my momentum? And if sound waves can indeed be accelerated, can they also be decelerated (not halted entirely, but delayed in some way)?
No. Sound travels at a speed determined by the medium in which it is being carried. Once created and on their way, the sound waves don’t know what speed the object creating them was travelling at. Your shout may be doppler-shifted by your speed (appearing shorter and at a higher frequency to an observer in front of you), but the time it takes to get to them won’t be changed by how fast you were moving.
Now, if you happened to have a 50KPH tailwind moving the air along with you as you were moving, then the sound would appear accelerated relative to a stationary observer. It’s the speed of the carrying medium which determines it.
Great… thanks for clearing that up!! Another related question that came to my mind after reading some of the replies…
It’s the speed of the carrying medium which determines it.
Would the same apply to radio waves too?
For example, suppose I had this spaceship currently in the vicinity of Jupiter and making its way to Saturn, and I wanted to send it an urgent instruction, would accelerating my transmitter to a certain velocity and THEN sending out the radio signal cause the signal to get there any faster, and could my signal be distorted in any way because of the acceleration? It being space, there wouldn’t be any scope for variation in the physical properties of the transmitting medium. Also assuming all the intermediate planets weren’t in the way.
Electromagnetic Radiation (radio waves, light, X-Rays, etc.) doesn’t propagate via any medium, first off (passing through a medium slows it however, or more correctly, causes it to be absorbed and re-emitted, which slows the overall signal). Travelling in the direction you’re sending the EM waves will increase their frequency (blueshift). The speed of electromagnetic radiation is a constant. One of the central findings of relativity is that you cannot add your speed to the speed of light you’re emitting.