First of all, I'm not certain on this, if I'm wrong I'll quite happilly bow to greater knowledge.
You've asked two seperate questions - one about the speed of light, and one about the speed of a bullet. And Rote 8 has added the speed of sound into the equation. Here's the way I understand it.
The speed of light is measured relative to space. If you are moving through space at the speed of light, and you turn your headlights on, then the light from your headlights would move through space at the speed of light too - so they would not light the way in front of you.
The speed of sound is measured relative to the medium the sound is moving in, usually air. Mach 1 is defined as that speed where your TAS (i.e. your speed relative to the air) is equal to the local speed of sound. So if you are travelling at Mach 1, the sound you produce will move at the same speed as you, and therefore will not propogate in front of you. However, notice the subtle difference between this and the speed of light - the speed of light is relative to space, whereas the speed of sound is relative to the air. Thus, with a strong tail-wind, an aircraft at Mach 1, and its sound-wave, will have a higher ground-speed than in still air (even if the temperature, and therefore the local speed of sound, were the same).
The bullet is different yet again, because the speed of a bullet is relative to the gun. So if you move your gun at the speed of a bullet, then fire it, I believe the bullet would be moving at twice the speed of a bullet. (Although, as Ludwig points out, it would slow down fairly quickly.)
I have no idea what this has to do with Private Flying, and I'm sure BRL will move it to somewhere where more educated minds can tell me I'm wrong! (Not that us private pilots aren't an educated bunch, of course!)
FFF
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