Both types of earthquake waves travel slower in less rigid material, such as sediments. For that reason, the speed of longitudinal or pressure waves (P-waves) in earthquakes in granite is significantly higher than the speed of transverse or shear waves (S-waves). The bulk modulus of granite is greater than its shear modulus. Earthquakes produce both longitudinal and transverse waves, and these travel at different speeds. ![]() Seismic waves, which are essentially sound waves in Earth’s crust produced by earthquakes, are an interesting example of how the speed of sound depends on the rigidity of the medium. The second shell is farther away, so the light arrives at your eyes noticeably sooner than the sound wave arrives at your ears.Īlthough sound waves in a fluid are longitudinal, sound waves in a solid travel both as longitudinal waves and transverse waves. ![]() The first shell is probably very close by, so the speed difference is not noticeable. Sound and light both travel at definite speeds, and the speed of sound is slower than the speed of light. I am not even sure how this sound would propagate down to the ground if you could even hear it at all.V=\sqrt Differentiating with respect to the density, the equation becomes On top of that, he is in an area where the density of air is quite small. In fact, he is a small object high above the ground so it would be hard to hear. There should be one, but it wouldn't break any windows or anything. Honestly, I am not sure of the exact answer. Image: Wikipediaīut I still haven't said if there was a sonic boom for Felix as he fell. At the flick of a switch, they shoot off the sides, with the driver or an Xbox-loving patrol officer at home base controlling the mono-wheeled UAV as it slices through traffic in hot pursuit.Ī Flying Pursuit Unit (or FPU – let's just call it a drone), deploys from the nose of the E-Patrol, equipped with a pair of video cameras, a 3D terrain scanner and radar which autonomously flies over traffic to scout out what's causing yet another massive backup on the 405. It looks like the mashup of two Tron Lightcycles stitched together with an AMOLED/carbon fiber roof, but those two massive rear wheel arches are actually single-wheeled drones that are magnetically attached to the body. Dick to create the E-Patrol Human-Drone Pursuit Vehicle. It's as if BMW's Southern California design studio channeled the unholy lovechild of William Gibson and Phillip K. Here is a plot of the speed of Felix as a function of altitude in terms of the Mach number (again, this is based on my not so perfect model). It has the definition of Mach number as the ratio of the speed of an object to the local speed of sound. I guess I was right ( at least according to Wikipedia). You should also notice that this calculation has his maximum speed a little over the reported value of 373 m/s - hopefully I can fix this later when I compare my model to the real data - but it's not too far off. You will notice that from this numerical calculation, Felix was going faster than the local speed of sound for about 45 seconds. Here is a plot of the speed of Felix as he falls along with the plot of the local speed of sound at that same time. I am using it to mean the speed of sound at the current altitude. I don't know if "local speed of sound" is an official term, but I like it. Was he also going faster than the speed of sound for the altitude he was at? Well, it makes logical sense that if the speed of sound is greatest at sea level and he went faster than the speed of sound he would be going faster than the locals speed of sound. Did he fall faster than the speed of sound at sea level? Yes. However, the question doesn't really make sense. ![]() Just from this data, you can see that Felix Baumgartner did indeed fall faster than the speed of sound. If you move up to 120,000 feet, the speed will drop down to around 200 m/s. ![]() At sea level, the value is right around the 340 m/s mark.
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