Critical Thinking 101

[TCDiver1]

Assume an airplane is sitting on an infinately accurate scale. Assume that the door is open and a bird flies into the plane but does not land while inside. Does the weight, as measured by the infinately accurate scale, increase or decrease?

Depends .....would the bird be African or European?

 

[Rick Murchison]

I think the "theoretical" answer would be that it remains the same as the displacement of frozen water is roughly equal to that of the same water in liquid form...

Just as in a drinkglass that is topped to the brim doesent overflow as the ice melts...

In this instance though, the air above sea-ice is very dry so the melting process would propably result in some watervapour being absorbed into the surrounding air, hence the actual waterlevel would sink "slightly"...

Talk about overthinking the problem.... You could also note that the "heat" (a negative value) of melting would drop the overall temperature of the water in the seas and also lower the level a little - but the main point is - as you noted - that ice displaces the same volume it'll occupy as water, so its melting has no (significant) effect on the water level.
Rick

 

[ArcticDiver]

LAX-HNL airplane:

Original criteria specified fuel consumption was not considered in the question. Even Diver?s A and B knew the airplane would lose weight due to consuming fuel. The airplane would be the nearly the same weight on landing as take-off. The bodily fluid and material transfer doesn't change the total weight. Since the airplane is pressurized gas transfers due to respiration are made up by the pressurization process.

But, kudos to the person who went outside the box to consider passenger dehydration. That will cause a small but theoretically measureable decrease in water weight. Even if the passengers maintained their water levels the replacement would have to come from on board fluid stocks which cannot be replaced in flight.

 

[The Kraken]

Well, we'd load the bird up with fuel, get it as close to a hover as we could, nudge the cylic forward, wear down the skids and we headed down the runway, hit transitional lift, get airborne, burn off a bunch of fuel because we were over-grossed to begin with, make the trip and land without rolling it up in a ball.

No 3 mile long runways or catapults to do the work for ya like Uncle Ricky was used to . . .

Once again, sorry for the hi-jack.

the K-opter Pilot

 

[miketsp]

Mike, the door is open.

the K

Doesn't make any difference. The bird is inside the plane.
If it's near the door the weight added to the plane may be less than 100% of the bird's weight due to leakage of the air flow but as long as the bird is over the threshold there will be a weight increase.
There would only be one practical exception to this statement. The plane is flying and the front and rear doors are open resulting in a significant air flow through the plane and the bird is flying in this airstream. Even so there will be a very slight deviation of this airflow downwards caused by the bird resulting in a vectorial weight addition to the plane and the need to generate additional lift from the wings.

 

[The Kraken]

Geeezzzzzz, I LOVE things like this !!!

the in K-wizitive One

 

[The Kraken]

OK, so, if I were to put a really big can on a very, very accurate scale with its open end pointing to one side, and then put my hand inside the can it would weigh more?

the K-westioner

 

[ArcticDiver]

OK, so, if I were to put a really big can on a very, very accurate scale with its open end pointing to one side, and then put my hand inside the can it would weigh more?

the K-westioner

Depends on when you measure.

Initially, yes it would. But, after the air content has time to stabilize, no it wouldn't.

You did say a "...really big can..." so their would be no gravitational or associated effects.

 

[The Kraken]

So, therefore, if the bird flew skyward, the weight of the aircraft would be reduced?

the K-ilogram

 

[irishsquid]

If the bird inhaled before entering the plane, then wouldn't there be an increase of total air weight?????????