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A Physics Question

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Turkeytop
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A Physics Question

Post by Turkeytop » Mon Aug 29, 2016 9:28 pm

It's August again. Wasp season. Every year at this time, my wife hangs out her wasp trap.

It's a bell shaped, glass jar, open in the bottom, so the wasps can fly up into it. She baits the trap with apple juice. Beer works too but I'm not sharing my beer with those bastards. They get inside, fly around until they're exhausted then drop into the liquid and drown.

Today I was having a beer on the patio, watching and enjoying their struggling. But it started me wondering about something.


The jar weighs a pound or two. The liquid inside would add possibly another half pound to the total weight. The weight of the wasp carcasses within the liquid would also add to the weight of the unit.

So my question is this. When a wasp fist enters the trap, but it is still airborne and buzzing around, does it have any effect on the total mass. I believe the answer is probably no. But once the creature enters the jar, it does displace some of the air that was there.



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TC Talks
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Re: A Physics Question

Post by TC Talks » Mon Aug 29, 2016 9:45 pm



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audiophile
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Re: A Physics Question

Post by audiophile » Mon Aug 29, 2016 9:47 pm

I depends on how much of the wing's propulsion is captured by the container.

It would say it mostly is captured and adds to the mass.


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Turkeytop
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Re: A Physics Question

Post by Turkeytop » Mon Aug 29, 2016 9:58 pm

audiophile wrote:I depends on how much of the wing's propulsion is captured by the container.

It would say it mostly is captured and adds to the mass.

Interesting.

Thank you.



jry
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Re: A Physics Question

Post by jry » Tue Aug 30, 2016 1:44 pm

I'll ask the family scientist, but in looking at your design, it looks like it only adds mass when it lands on the jar. Reason being that it's open air on the bottom.



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Plate Cap
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Re: A Physics Question

Post by Plate Cap » Tue Aug 30, 2016 11:16 pm

Turkeytop wrote:
So my question is this. When a wasp fist enters the trap, but it is still airborne and buzzing around, does it have any effect on the total mass. I believe the answer is probably no. But once the creature enters the jar, it does displace some of the air that was there.

My training is in electrical engineering, not wasp statics and dynamics, but from your photos, here is my SWAG:

The wasp's weight is offset by his muscle action while compressing air under him. I don't think wasps near-hover based upon much effect from wing chord rarification, such as how a wing of airplane works. I would surmise, at hover or near hover, it's merely reaction of the muscle action against the air....similar to us treading water.

Some of that compression weighs upon the pool at the bottom, most of it probably escapes through the large hole.

So, if any of that is valid, and I think at least some of it should be, the effect upon the 'weight' of the bottle of the still-flying wasps is probably pretty negligible.

I've always meant to weigh an 'empty' tire, fill it with 35 PSI of air, and weigh it again. Been thinking about that since I was a kid; never got around to it. Must put that on my bucket list.


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