Re: Downwind Fish

TexMex:

I never thought about your observation, but it makes perfect sense to me. Often I have caught fish with missing fins, or more frequently, fish with damaged fins.

Considering the increased density of water compared to air, it is only logical that the "downstream turn" must be the culprit.

You should do a little more work on this theory and submit your documentation for "Peer Review" here on the newsgroup.

Yuck it up folks....give the guy credit for coming up with a new twist on an old argument .... LOL.

Lee

I think he skipped the lime juice and the salt when makeing those margaritas. :)

Which all goes to show how little you understand.

However I am not going to disillusion you.

By golly -- My calendar must be off a bit! I didn't realize today was April

Ah, but it is I who am disallusioned; I thought the "avid fisherman" line was a dead giveaway!

I studied aeronautical engineerig in school, and used the analogy of a fish in a stream to try to disport the belief of a friend who ascribed the demise of this Telemaster to a turn downwind. The fish NOT sinking to the bottom when turning downstream seemed to put the concept across. We all got a chuckle, and I thought the board might too.

I was attempting humour, an endevor my wife tells me I should leave to professionals. So be it.

Connan the Shadenfreuded

Nice Troll! ;-))

I liked it...

Dr.1 Driver "There's a Hun in the sun!"

Its not just a fish problem. I badly twisted my knee the other day when I too quickly turned into the direction of the earth's rotation. You have to be careful when walking on a rotating planet!

Momentum can indeed be a problem, if there's too little of it. For those convinced of the hazards of the downwind turn, extra momentum is available from these guys:

I'll give a real puzzler for relativity tho.

If all motion is relative, how come my arms flap out when I twirl around....surely its no different from the rest of the universe going round me, as I remain still...

(hint: you really DO need relativity theory to sort this one out)

Perhaps your arms WOULD flap out if the universe spun around you as fast as you twirl around.

Dan

Yes, that is correct, but what is the explanation ? :-)

OK, I'll bite. Having just reread Einstein's own introductory paper on the special and general theories of relativity for the fourth time, I still can't see that this is correct. The two frames of reference (you and the universe) are accelerated relative to each other, and so should not be transparently interchangeable. Please explain.

-tih

Since you are mving with the universe, any changes have to be made by YOU. The reason your arms don't fly up by themselves is that your position is relative to gravity, not the movement of the universe.

Not sure I understand what you're saying here, but if I understand TNP correctly, he claims that if all the (other) matter in the universe were to start rotating around you, your arms would flap out. I can't see that either classical physics or Einsteinian relativity can in any way support that statement. According to the principle of relativity, the same rules hold within frames of reference that are moving at a constant, linear velocity relative to each other. In the scenario under discussion, the principle of relativity does not apply.

-tih

You forgot. He is "SPECIAL".

I asked ths question of my physics master years ago at age 14, he galred at me - he had a Phd in nuclear physics and said. "The rotation is defined relative to the fixed mass of the universe" So I think Paul is right. If the fixed mass of the universe were to rotate round me, my arms WOULD flap out even tho I remained standing still..

If you like, velocity is relative, but acceleration is absolute. And the frame of abolute zero acceleration is the average of the gravitational pulls of everything in the universe. Or something. I did engineering, not physics, at university :-)

Your movement perpendicular to the force of gravity is what causes your arms to raise. The elusive centrifugal force. Your arms are relative to your body and the force of gravity.

I'm no physicist, but I think that if the universe appeared to be rotating, it would be YOU that was rotating. What is the universe, anyway? Is it contained within some larger thing which defines the term "fixed?" And what would be this larger space, and what would be beyond it? And the

Again, I don't know, but I don't think gravity is the only thing at work here. All the textbooks that discuss gyroscopes tell us that while spinning they are rigid in space, not rigid with reference to average gravities. The gyro generates its own forces in its plane of rotation.

As far as the downwind turn thing, I have been flying full-scale since 1973, and while doing turns in a constant wind, I have never felt any forces associated with turning upwind or downwind. We teach precision steep turns as part of the college-level flight training here, and if the phenomenon existed we would notice either a decrease in altitude or airspeed or both as the aircraft came around to point downwind, and the opposite when it came to face upwind. We don't, and none of the textbooks mention it. We operate in upper winds that are a significant percentage of the airplane's cruise speed, too, sometimes strong enough that we are able to hover over a point at lower speeds. If the inertial forces are there, they are negligible. Remember that the gyroscope is rigid with respect to space, and the airplane's turn is relative to space, too, since the earth's gravity does not act in the horizontal plane. I believe the modeler is deceived by the higher groundspeed generated by turning downwind, and may reduce power to compensate. Altitude and airspeed will certainly suffer in such a case. The modeler may also be influenced by the Doppler shift in engine sound.

Dan