Sound/Waves

[dartmed]

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Ok, are there specific formulas that tell you how the velocity of sound is different medium? I understand that the velocity of sound is greater in solids than liquids, and faster in liquids than gases. For instance, if a question asked how does the velocity of sound change when traveling from a steel rod to a glass of water? Is there a formula for that?

Why does sound travel faster in monoatomic gases than diatomic gases? I thought greater the number of particles, the greater the chance of compression, hence faster the sound waves? Am I thinking this the wrong way?

How do I know what types of waves travel through what mediums? For instance, if I were to strike a rod with my fist, what type of waves are transmitted through the rod (longitudinal, standing, or traverse)? What if I throw a stone in the water? What waves are transmitted by the ripples caused by the waves?

Sorry for so many questions, but would appreciate all the help!! Thank you.

 

[dartmed]

Ok, are there specific formulas that tell you how the velocity of sound is different medium? I understand that the velocity of sound is greater in solids than liquids, and faster in liquids than gases. For instance, if a question asked how does the velocity of sound change when traveling from a steel rod to a glass of water? Is there a formula for that?

Why does sound travel faster in monoatomic gases than diatomic gases? I thought greater the number of particles, the greater the chance of compression, hence faster the sound waves? Am I thinking this the wrong way?

How do I know what types of waves travel through what mediums? For instance, if I were to strike a rod with my fist, what type of waves are transmitted through the rod (longitudinal, standing, or traverse)? What if I throw a stone in the water? What waves are transmitted by the ripples caused by the waves?

Sorry for so many questions, but would appreciate all the help!! Thank you.

Anyone? Please?

 

[rjosh33]

Ok, are there specific formulas that tell you how the velocity of sound is different medium? I understand that the velocity of sound is greater in solids than liquids, and faster in liquids than gases. For instance, if a question asked how does the velocity of sound change when traveling from a steel rod to a glass of water? Is there a formula for that?

None that I'm aware of. And almost certainly none you would have to memorize for the MCAT. But you should know why the speed changes in the different mediums. Does the wavelength or frequency increase/decrease? Or both?

Why does sound travel faster in monoatomic gases than diatomic gases? I thought greater the number of particles, the greater the chance of compression, hence faster the sound waves? Am I thinking this the wrong way?

Tricky question. I had to look this one up. The best explanation I've found is that monatomic gases can only transmit energy due to the compressions as translational energy, whereas diatomic (and polyatomic) can also store the energy as rotational. Thus the adiabatic compressions raise the temperature of monatomics higher, which allows the molecules to compress more quickly, propagating the overall wave at a faster rate.

How do I know what types of waves travel through what mediums? For instance, if I were to strike a rod with my fist, what type of waves are transmitted through the rod (longitudinal, standing, or traverse)? What if I throw a stone in the water? What waves are transmitted by the ripples caused by the waves?

Both longitudinal and transverse waves can travel through a solid. However, only longitudinal waves can propagate through a liquid, as the liquid is unable to provide the restoring force a transverse wave requires (same goes for gases). Light, of course, is the exception, as electromagnetic waves are considered transverse but are also self-propagating, and don't require any sort of medium in which to travel.

Beyond the above, there's little chance you have to know which wave travels when.

Sorry for so many questions, but would appreciate all the help!! Thank you.

No problem. Not sure if I helped or made it worse, but you definitely want to know all the basics on waves for the MCAT. It's one of those topics you can expect at least a discrete or two testing it, if not an entire passage.