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Originally posted by mbhcsf at 7/12/06 06:48 AM
how about the principle of ultra sound and its application in medicine? especially during the scanning session i know that the human tissues will absorb the sound and hard tissue could be reflec ...
ultrasound is not intended to resonate the body of the baby (at least i dont think so). ultrasound is just a sound wave that has high frequency, higher than humans can hear. it it's not necessarily the resonant frequency of certain bones. and i'm pretty sure they'll aviod such frequencies.
not only the right frequency, the size of amplitude also matters. even if the frequency matches the resonant frequency of a certain bone, it may not be shattered due to low forcing amplitude and/or high damping of the structure. |
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by mbhcsf
wonder what would the physiotherapist expected when they are doing ultra sound scan on the patella....
Hmm ... I wonder if it really safe to use Ultra Sound Scan? :hmm: |
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amplitude... resonant... diffraction... crystal...
gelombang air datang, tsunami melanda kat satu bangunan yg tak kukuh, bangunan runtuh jugak. Tapi kalau bangunan tu kuat, pembelauan dan sedikit pantulan mungkin berlaku.
jadi, kalau gelas kaca tu bertahan, terbelaulah gelombang bunyi... terpantullah sket... kalau tak tahan, kene gelombang dah bekecai, ape lagi nak dibelau dan dipantulkan?? abislah, takde lagi halangan sebesar sebesar gelas tu...
ceh.. ceh.. aku teka je ni... tak blaja sangat pasal gelombang... kalau salah, tolong betulkan ye... :bgrin: |
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Reply #23 aku_EnSeM's post
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eh, ape plak aku cakap ni??? :stp: |
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cube fikir.....kenapa NAVY x berkawad atas kapal? sape yg pakar fizik mesti boley jawab.... |
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Reply #26 zulyusoff's post
:pray: :lebai:
dan tugas manusia untuk discover punca2nya... |
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basically,ade dua sebab yg boleh menyebabkan gelas tu pecah..
first,common punye knowledge...if that sound was to powerful,it will brake the glass...force yang bunyi tu exert on the surface of the glass membekalkan energy to molekuls,menyebabkan molekul itu bergetar dengan kinetic energy yang llebih kuat dari daya tarikan antara molekul2 glass tersebut,menyebabkan ikatan antara molekul terlerai...A force that act on an object can brake that object..and force tu xsemestinya by some action(ketuk,pukul,etc),as long as its contain energy,it can break the bond between molecule...just like when we heat water...water will change into stim after some times,...but it is very2 rare for us to see an event where sound can break a glass...
secondly,reasonan theory..benda ni complicated skit coz melibatkan frequency between two object...and if a sound break a glass,i think impossible to tell wether it was cause by the first or second case...
but one thing for sure..sound can break a glass...100% sure... |
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yup,sound can break glass...scientifically proven.fenomena ni dipanggil "standing wave"...gelas akan pecah bila amplitud getaran dah menjadi terlampau kuat untuk gelas tuh.penyanyi penyanyi tenor (pavaroti) dengarnye boleh pecahkan gelas dgn suara die...huhu... |
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Originally posted by GhostRecon at 7/30/06 11:09 PM
penyanyi penyanyi tenor (pavaroti) dengarnye boleh pecahkan gelas dgn suara die
in terms of frequency, tenor is relatively low. but it's still possible for him to break the glass, if the glass has low natural frequency. or even if he can't reach the natural frequency, he may still break the glass producing very very high amplitude of wave. |
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that's interesting.just wanna ask..coz sometimes im a bit confused...which properties breaks the glass...is it the frequency or the amplitude...this question is as same as "which one kills a person,the voltage or the current" :hmm: |
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apa kata ko cuba sendiri.. cari beberapa jenis gelas dan benda kaca letakan behampiran speker yang agak kuat... cucuk mic buat feedback dari beberapa tempat.. nanti mngkin ada yg pecah.. |
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Originally posted by pala_hotak_lu at 16-7-2006 01:33 AM
cube fikir.....kenapa NAVY x berkawad atas kapal? sape yg pakar fizik mesti boley jawab....
sama konsep dgn bagaimana cermin boleh dipecahkan oleh bunyi...bila ramai2 berkawat atas kapal, tenaga daripada hentakan kaki dipindahkan ke atom2/molekul pada kapal..these atoms/molecules will vibrate, if the vibration is violent enough as to approach its resonant frequency, disaster will happen..:nerd: |
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Originally posted by aphrodisiac at 2-8-2006 08:31 PM
sama konsep dgn bagaimana cermin boleh dipecahkan oleh bunyi...bila ramai2 berkawat atas kapal, tenaga daripada hentakan kaki dipindahkan ke atom2/molekul pada kapal..these atoms/molecules wi ...
Acceptable.....kapal tu boleh patah...... |
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maresiajin This user has been deleted
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pasti boleh , kalau frekensi tinggi |
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Category: Belia & Informasi
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Post time 13-7-2006 03:51 PM
