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Old June 30 2013, 05:05 PM   #1025
sojourner
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Re: MAN OF STEEL - Grading & Discussion

CorporalCaptain wrote: View Post
sojourner wrote: View Post
CorporalCaptain wrote: View Post
No, what you said was that most aircraft would disagree with the idea that momentum must be conserved (because what I said was nothing more than that). That's false; it must be.

Also, I was talking about Superman changing his trajectory, which, if it were to occur under real world physics, would mean that a compensating force must be applied to another body. For example, say he's floating stationary right next to Lois Lane one second, and then the next second, he's flying away at 500 miles per hour. If the compensating momentum were imparted to Lois, she'd be dead.

Now, am I saying that has to occur? No, I explicitly said that that level of realism is not necessary. I simply said, it would plausible if it did kill her.

Edit: And I also said that the momentum could be imparted to a massive and virtually stationary body, such as the Earth itself. Of course, this need not occur, either.
Two words from your original post that I quoted. "during flight"

Then in your followup post you introduced lift, as seen above.

A change in trajectory can be achieved through flight without using "outside forces"as my example above demonstrates. Now instead of trajectory, maybe you meant to say velocity?
Everything I said was correct. Trajectory means in the sense of a curved path under the effect of forces including friction due to air resistance, and gravity. I mentioned lift only because you mentioned airplanes, as if they were somehow special; they're not. The thing that distinguishes airplanes from other vehicle is their wings, but the way that wings generate lift still involves conservation of momentum.
And yet, my original statement and example still stands while your example of superman floating next to Lois works much better if you replace "trajectory" with "velocity".

Regardless, Superman has been shown to change trajectory and velocity without affecting those near him.
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