Hahaha, my physics problem

[Foehammer-1]

I remember a few years ago someone posted that they had a U-boat physics problem...

Well, today, here is what I had to solve:

"An ultrasound unit sends a 3.70 MHz sound wave into a 28.8 cm long tube filled with an unknown liquid. A small microphone right next to the ultrasonic generator detects both the transmitted wave and the sound wave that has reflected off the far end of the tube. The two sound pulses are 3.50 divisions apart on an oscilloscope for which the horizontal time sweep is set to 94.0 µs/division. What is the speed of sound in the liquid? "

Sonar, anyone? http://forums.ubi.com/images/smilies/88.gif

[Celeon999]

Thats nothing !

Go to your teacher and ask him to explain you the casimir effect. http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

That will make him/her sweat.

Vaccum fluctuations. A perfect vaccum, no matter, no radiation , no temperature.

You put two metall plates into this "space" of nothing , each plate just 11 nanometers apart from each other.

What happens to the plates ? Nothing you will say. Physics and logic dictates that nothing will happen.

Wrong. http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif Booth plates get pushed together, and as closer they get to each other the higher the push force gets.

And remember they are getting pushed, they do not pull each other like through magnetism or something. The force does not come from them.

The vacuum, the absolute perfect nothing, the absence of simply anything.... puts a force on the plates.

Try to convince somebody of that. http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

But its a scientific fact that was foresaid through mathematics by a dutch physician (Professor Casimir) in 1948 and evidenced by somebody else (cant remember the name) 10 years later in 1958.

Or simply watch the fourth Season of LOST to get even more confused http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif


Season 4 Trailer "The Orchid" (http://www.youtube.com/watch?v=6co-gFxMIqo)

[K_Freddie]

Ahhh..
The borderline between macro-gravity and electro static forces, talk we not... as we're now on the atomic scales...
http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif