Going the speed of light, possibly.

[DrWafflez Jr.]

I have a question, my bestfriends dad said that if we were driving at 70 mph and then honked the horn, the sound would go 70 mph + the speed of sound. So the obvious question, if that is true can we go the speed of light? But sound is the vibrations of atoms? Does that mean the atoms would have to bump into each other at the speed of light? Last but not least can this be accomplished with a gun being shot or something of the sort? Thanks in advance

 

[DennisN]

So the obvious question, if that is true can we go the speed of light?

No. At relativistic speeds, you can not add velocities like you usually do, because of special relativity. See Velocity-addition formula (Wiki) and Einstein Velocity Addition (HyperPhysics).

 

[Ryan_m_b]

Your friend is incorrect, the speed of sound through a medium is not affected by the speed of the emitter.

 

[Nugatory]

I have a question, my bestfriends dad said that if we were driving at 70 mph and then honked the horn, the sound would go 70 mph + the speed of sound. ... Last but not least can this be accomplished with a gun being shot or something of the sort? Thanks in advance

Honk the horn and the sound will travel at the speed of sound no matter the speed of the source - sound waves have a particular speed in the air and that's the speed the move at.

Fire a bullet forward from a moving car and the speed of the bullet relative to the ground will be given by the velocity addition formula DennisN mentions ($\frac{u+v}{1+uv/c^2}$) where $u$ is the speed of the car relative to the ground and $v$ is the muzzle velocity of the bullet. For cars and bullets and other slow-moving objects (here "slow-moving" means not tens of thousands of miles a second) this formula reduces to the $u+v$ that common sense tells us to expect.

 

[sardar]

Thank you for your question. While it is true that sound travels at a certain speed, it is important to note that this speed is relative to the medium in which it is traveling. In this case, the medium is the air inside the car. So, when you honk the horn while driving at 70 mph, the sound will still travel at the speed of sound relative to the air inside the car, which would be approximately 343 meters per second. This does not mean that the sound is traveling at 70 mph + the speed of sound.

As for your question about going the speed of light, it is currently not possible for any object with mass to travel at the speed of light. This is due to the laws of physics, specifically the theory of relativity. According to this theory, as an object approaches the speed of light, its mass increases infinitely and it would require an infinite amount of energy to accelerate it to that speed. Therefore, it is not possible for atoms to bump into each other at the speed of light.

Furthermore, even if an object could travel at the speed of light, sound would not be able to travel at that speed because sound requires a medium to travel through, and at the speed of light, there is no medium for sound to travel through.

In regards to your question about a gun being shot, the bullet would also not be able to travel at the speed of light due to its mass. It would require an infinite amount of energy to accelerate it to that speed.

I hope this answers your questions and clarifies any misunderstandings about the speed of light and sound. As scientists, we continue to study and learn more about these concepts and their limitations.