Calculate the length (L)?

Question

http://s248.photobucket.com/albums/gg177/Maxwell078/?action=view¤t=L.jpg

Answer 1

I ma not going to calculate you anything, sorry.

Move to usenet newsgrop sci.physics and ask questions there, or similar uncensored place, and the help will arrive.

Answer 2

Hi Cat, Edward, Jack:



I stared at the picture and could never figure out what the question was. I finally looked at one of Jack's other pictures, re-read Edwards answer and then realized that those were swim fins on the clown. The barrel in the second picture has been pushed underwater (I guess today is my stupid day)



Anyhow, the answer depends on atmospheric pressure and fluid density



The pressure based on the compression of the gas will be:



P = Patm*3m/L



The pressure based on the fluid will be the



P = Density *L*g +Patm



If we assume that the fluid the clown is swimming in is water, then Density = 1000kg/m^3, then:



P = Patm*3m/L = 1000kg/m^3 *g*L +Patm



Patm*3m = 1000kg/m^3 *g* L^2 +Patm*L



0= 9800kg/m^3 * L^2 +Patm*L - Patm*3m

*[ %^$#& quadratic equation]



0= 9800kg/m^3 L^2 + 101 kPa *(L - 3m)



Solving L = 2.42 m or -12.7 m



Note: L = -12.7 is a very real answer which corresponds to the water being sucked up 10 meters and another 2.5 m of vacuum on top.

...........................



While I was trying to solve this thing, Edward did the same, but he made an educated guess to avoid the quadratic. That extra .1 m in accuracy was not worth the effort. Now he is off offerring vodka to the Cat.

Answer 3

Hmmm ...

Hi Cat, long time no see. I like your answer...I give you one thumb up for being close.

However I wonder if B. Pascal could agree with you? The pressure inside that bell must be the same as the pressure 3 m below the surface of that fluid. So what is that liquid? Is it water? Let it be water p= 1000kg/m^3

So the pressure at the bottom of the bell is

P=pg h

and approximately the air inside the bell will be compressed to that pressure

P1V1=P2V2

V2=(P1/P2)V1

or since the bottom area of the cylindrical bell is the same

L= (P1/P2) h

Calculations! Okay.

assuming that P1 is 1 atm

P2= P+P1

1 atm = 101,325 N/m^2

L= ( 101,325/ (101,325 + 9.81 x 1000 x 3)) L = 2.3 m give or take a few mm .



My dear Cat vodka it is. How else would I be familiar with this problem () Sorry.

However I use specific gravity of 1.0, for water, as not to attract unnecessary attention.



Hey Jack, is it water or vodka? I'll drink to that too.



Hello Remo,

"Note: L = -12.7 is a very real answer which corresponds to the water being sucked up 10 meters and another 2.5 m of vacuum on top."

LOL Thumbs up to you for good humor and the quadratic (Never give up and never surrender! That 's the spirit!)



PS Yes, this is why I said 'approximately' ;-).

Answer 4

What is this?

It says 3 meters!

Here L=3