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Thanksgiving turkey
2

Thanksgiving turkey

Thanksgiving turkey

(OP)
The thanksgiving holiday is fast approaching and in that spirit, here is a problem to ponder over the holidays.
A submarine is submerged and stationary 500ft below the surface of the ocean.
In a cabin right next to the chow hall, a 100lb turkey was resting on a table when it happened to overhear two cooks discussing plans for the upcoming thanksgiving dinner.
What it heard threw it into a panic and it flew into the air and began to fly around the cabin in great distress.

Question: has the equilibrium/buoyancy of the submarine changed?  

RE: Thanksgiving turkey

I recommend that they get that baby in the oven soon if they plan on eating by thanksgiving.
We once raised a 60lb turkey. That sucker took 8 hours to cook. It kept springing the oven rack so we supported it with 2x4 blocking.

As for the buoyancy. No it will be the same. The mass hasn't moved outside of the sub.
Myth busters covered this.(except with pigeons and then a toy helicopter) The air from the wings is pushing down with a force equal to the mass lifted.
 

RE: Thanksgiving turkey

100 # turkey?  

RE: Thanksgiving turkey

What?  No treadmill?

RE: Thanksgiving turkey

Must have been on Captain Nemo's Nautilus--one of those birds they hunted on Mysterious Island.

RE: Thanksgiving turkey

Back to the OP, by what mechanism do you postulate the turkey was flying?  There is an equal and opposite reaction - do a free body diagram of the wing in air.  So as the way-too-fat-to-fly turkey takes wing, the downforce generated within the air mass by Tom's wings pushed down with the same net force as if he were still standing on the floor.

RE: Thanksgiving turkey

Only 100 lb turkey I ever met was my brother when he was about 6!!

BTW - Port is right!!

RE: Thanksgiving turkey

IR is probably right - but TRY to measure them!!!

RE: Thanksgiving turkey

(OP)
TX..forgot to mention that while flying the turkey glides for a period then remembers the gravity of his situation and starts flapping his wings frantically again....
I don't fully understand how a local pressure differential at the wing of the turkey can translate into a gravity event for the submarine as awhole...
IR..if the turkey stops generating lift for a second or two(begins to freefall), is the equilibrium condition still vaild?   

RE: Thanksgiving turkey

The centre of buoyancy will remain unchanged, but the centre of gravity will have changed.  So there will have been 'some' movement to your sub.  But the changes will be so miniscule.  

So what happens once all the guys catch, and eat said turkey?  

RE: Thanksgiving turkey

I've never quite bought into the notion that it's a steady state result.  I'm not convinced that Mythbusters carried out a valid experiment, as they often do.

However, one can possibly look at it as a conservation of momentum problem, so there are impulsive events that are directed at the submarine, as the turkey flies or changes direction.  

I completely agree that such impulses are absurdly tiny, given that something like the SSN John Warner has a gross weight of 7800 tons.

TTFN

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RE: Thanksgiving turkey

SAIL3,

   It does not matter if the turkey is flapping or gliding.  The wings vector air downwards to generate lift.  If the turkey were to switch from flying to ballistically hurtling for a bit, there would be an increase in the sub's bouyancy followed by a reduction in the bouyancy when the turkey either crashed or generated extra lift to climb back to his original altitude.   

               JHG

RE: Thanksgiving turkey

NO - it doesn't matter whether the turkey is flying or setting on his butt.  The buoyancy will remain the same - but as noted the CG may change if he walks or flies the length of the sub.

FedEx flies baby chicks all over the US and they still charge by the pound - because they KNOW!

RE: Thanksgiving turkey

Oh boy, a dynamic question on a structural engineering blog!

Using equivalent static analysis, the Turkey Load, TL = W x Ct
W = 100 lbs
Ct = St / R, where St = Design turkey response acceleration parameter (we'll use 1.5 for a fat yet agile turkey) and R = turkey table response modification factor(not given but we'll assume 3.5 for ordinary moment resisting steel table frame design).

So TL = 43 lbs over the fundamental buoyancy period of the submarine, T.

Since T requires an incoherent model we will use the approximate period, Ta = Cs h^x where Cs = approximate period structural parameter (0.01 for submersed steel cylinders), h = length of the submarine (560 ft for a typical Ohio class) and x = approximate period exponent parameter (0.95 for submersed steel cylinders)

So T = Ta = 4.08 seconds

In conclusion, a Turkey Load of 43 lbs will unbalance the submarine for a period of 4.08 seconds until equilibrium is returned.

 

RE: Thanksgiving turkey

SAIL3,
Please advise what engineering school you graduated from (if you did).  My son needs to make his choice soon ...  

RE: Thanksgiving turkey

(OP)
ok..let me continue with this saga...
the turkey is flying around the cabin and this went on for 5 days and nights, no rest and no food, as a result the turkey began to lose weight and strength until finally it collapses back on the table, after having lost 50lbs and too exhausted to care anymore, come what may(kinda like how some design projects wind up)...

same question: has the equilibrium/buoyancy of the submarine changed?  

RE: Thanksgiving turkey

Of course it changed after such a long flight.  The sub used up 5 days worth of fuel.  

Probably one of those old diesel subs where they had to bring in livestock for food since they had no modern refrigeration.  Serious odor problems on board.  

RE: Thanksgiving turkey

It takes 2.5lb of food to raise 1 lb of turkey

This gives the equation -->
Total weight  = 2.5*Delta Turkey

Also this particular turkey lost 50 lbs (Delta turkey = -50)

Because we know all equations are reversable this gives us
Toal wt = 2.5 (-50)=-125

Therefore the sub lost 125 lbs thus changing the boyancey.

RE: Thanksgiving turkey

The turkey's sweat and $hit still fell on the floor!!

RE: Thanksgiving turkey

SAIL3,

   Unless the turkey's mass somehow exits the sub, there should be no change to buoyancy due to the turkey.

   With a 100lb turkey rampaging around the sub, there may be a change in buoyancy due to sailors using the escape hatch.  

               JHG

RE: Thanksgiving turkey

Mass can't be destroyed- just converted to a different form (unless the turkey flies into the nuclear reactor- then it could be converted to energy). Since this is a closed system, the extra 50 lbs the bird lost needs to go somewhere.

No effect on buoyancy due to this factor alone.
 

RE: Thanksgiving turkey

Buoyancy can be thought of as the effective density of the object relative to the water displaced.  The physical volume of the sub does not change, and variance in apparent weight is rather miniscule.  

A brute force estimate would be 100lb*500ft/(7800ton+100lb) = 0.98mm.  

In a real ocean with real currents and waves, that's prit near undetectable.

TTFN

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RE: Thanksgiving turkey

Why the 500 foot lever arm?   

RE: Thanksgiving turkey

I think we should simplify things and look at the turkey on the International Space Station first.

In this case there is no change in the external forces on the ISS, so whatever the turkey does has exactly zero effect on the position of the centre of mass of the ISS (including the turkey and the air).  Any movements of the turkey are balanced by equal and opposite changes in air density, and small changes in the position of the structure of the station.

Back in the submarine, if we assume (for simplicity) that the turkey takes off entirely by interaction of its wings with the air, as it takes off there will be a balancing compression wave in the air.  For a short period the centre of mass of the submarine (including turkey and air) will remain exactly on it's previous course, but when the compression wave hits the surface of the submarine there will be some small interaction between the surface and the water, and there will be a small change in the external force on the submarine, and hence an accelleration.  This will be balanced by a compression wave going off through the ocean, and eventually through the Earth, so there will not be any change in the path followed by the planet, no matter how carefully we measure it.

All these changes (other than the change of air pressure under the turkey's wings) are much too small to measure in practice.

Doug Jenkins
Interactive Design Services
http://newtonexcelbach.wordpress.com/
 

RE: Thanksgiving turkey

A 100 lb turkey must be an ostrich.

Andries

RE: Thanksgiving turkey

If the turkey jumps up and down in the roasting pan in the kitchen of the sub, the instantaneous buoyancy of the sub changes.  If I jump up and down on the bathroom scale, the instantaneous reading will change; however, the average will remain the same less the lost efficiency of a fat guy sweating and loosing heat.  

RE: Thanksgiving turkey

T-day is in a couple of days - send me that 100 lb turkey and I will cook it, eat it and put an end to this mess....

RE: Thanksgiving turkey

the Real equation:

100# muscular turkey onboard SSN / SSBN + [2ea. to 20ea. farmboys] + probability of 0.08 of Cajun in crew =

5 to 18 lb segments of marinated turkey run thru deep-fat fryers until golden brown and ready to eat. NOTE: weight gain due to injection of marinade will be offset to within 18.73% due to the water loss inherent in deep-fat frying  All water converted form liquid to vapor will be deeply inhaled by hungry crewmen, thus maintaining a balanced water quantity, with only phase change losses generating more heat and chaotic conditions.

THUS: the net equibrilibrum of said submarine will remain balanced until such time as the Sanitary Waste Dispisal NCO blows out the contents of the Sanitary Holding Tank.  

            Q.E.D.

RE: Thanksgiving turkey

(OP)
ok here is my take on it....
turkey resting on the table....gravity forces resisted by buoyancy
                               forces equals equilibrium.

turkey starts to fly....energy of turkey is resisting gravity
                        force of turkey...submarine rises
                        accordingly to reflect the 100lb change..
                        This implies that the weight of the turkey
                        is being resisted by the energy expended
                        by the turkey and not by a buoyant force,
                        otherwise, one would be doubling the
                        resisting force..


turkey losing weight...the energy expended by the turkey to defy
                       the force of gravity..

turkey lands back on table....50lbs lighter..submarine sinks to
                              account for the now static 50lb
                              bird.

total change in buoyancy is 50lbs ..the 50lbs lost was expended
energy, say heat generated,etc...
This seems to defy logic and may be incoherent but I'm sticking to it until proven otherwise,which may not take long...

RE: Thanksgiving turkey

Imagine for a moment, a turkey riding on a flatbed truck. As the truck rolls along the turkey causes a constant force, then it decides to jump, it flexes it's knees, reducing the force until suddenly increasing it to gain escape velocity by straightening it's legs.

Does it's head cut through the air above or does it raise a column of the air? I don't know, do you?

Apply to the wings pushing up and down and similar questions must be answered first.

Michael.
Timing has a lot to do with the outcome of a rain dance.

RE: Thanksgiving turkey

>>

Orbital examples are not the same problem, because orbital objects are in freefall, and aside from microgravitational aspects, are completely superimposable.Turkeys are not rockets, so they cannot move without pushing against something, be it air or the floor.

<<

But turkeys are not rockets when they are inside a space station either.  

The submarine example is not the same as the orbital one because the submarine interacts with the water, but in the brief time while the air compression wave travels from the turkey wing to the surface of the sub, they are the same.

Doug Jenkins
Interactive Design Services
http://newtonexcelbach.wordpress.com/
 

RE: Thanksgiving turkey

(OP)
as the turkey flies around it flaps it's wings then glides for awhile, then flaps it's wings again...

during the wing flapping....ok there may be a compression wave
                            generated, but this an internal
                            pressure wave and does not change
                            the buoyancy of the sub.
                            Now, however, an external pressure
                            wave on the sub would cause it to
                            momentarily change the buoyancy.

during the gliding....to generate lift on the wing the air
                      pressure underneath the wing can remain the
                      same as surrounding air but the air press
                      over top of wing is less than surrounding
                      air, thus generating lift. This is a local
                      condition and does not generate a
                      compression wave. At least, this how I see
                      at the moment..






    

RE: Thanksgiving turkey

It time to "cook" this bird!!

RE: Thanksgiving turkey

Sail3 - it's mu understanding that gliding involves a pressure increase under the wing, as well as a pressure reduction over the wing, but it doesn't matter for this discussion.  It is these pressure differences that are holding the turkey up, and when the pressure waves hit the surface of the submarine there will be an interaction with the surrounding water.

Doug Jenkins
Interactive Design Services
http://newtonexcelbach.wordpress.com/
 

RE: Thanksgiving turkey

(OP)
the day before thanksgiving, the two cooks decided to check in on their beloved bird and were shocked to see the sorry state of the turkey.
They realized immediately that they had to make other plans for the thanksgiving dinner.
So now their challenge was how to make spam in a can look like and taste like turkey..
All's well that end well..so the turkey's life was spared.

So what lessons in life are we to learn from this saga??

thin is good?

fight or flight?..choose flight!

don't sweat the small stuff, but really really sweat the big stuff! etc.

Happy thanksgiving to all!!

RE: Thanksgiving turkey

I'd take a Spam turkey over a tofu turkey any day!

RE: Thanksgiving turkey

Ok, I thought Turkeys counldnt fly?

What are you Mr Carlson?

RE: Thanksgiving turkey

Anyone get this big Turk in the over yet?!

Its gonna take a while and tomorrows the big day.

RE: Thanksgiving turkey

"It's a helicopter, and it's coming this way. It's flying something behind it, I can't quite make it out, it's a large banner and it says, uh - Happy... Thaaaaanksss... giving! ... From ... W ... K ... R... P!! No parachutes yet. Can't be skydivers... I can't tell just yet what they are, but - Oh my God, Johnny, they're turkeys!! Johnny, can you get this? Oh, they're plunging to the earth right in front of our eyes! One just went through the windshield of a parked car! Oh, the humanity! The turkeys are hitting the ground like sacks of wet cement! Not since the Hindenburg tragedy has there been anything like this!"

 

"Good to know you got shoes to wear when you find the floor." - Robert Hunter
 

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