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I have formal training in physics, but tend to approach it very intuitively; I prefer estimation over exact calculation, principles over details. I believe many problems can be solved by making a careful sketch. Label your axes, and don't use insignificant digits.

I visit this site in the hope of sharing my enthusiasm and occasional insights with others.


12m
comment Does a person inside a falling bus fall to the front of it?
Good point about the fact he probably started falling before the bus was free from the bridge. If you go back to 0:58 in the movie clip you see Isaac come out of the bathroom - the shift in center of gravity may have precipitated the fall. I do think that the scene that shows him hitting multiple chairs without apparently losing momentum relative to the bus still appears to imply that he is accelerating relative to the bus even when the bus is in free fall. On the first hard "bounce" (at 1:12) he should have slowed down a lot. Not exactly "weightless"...
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revised Does a person inside a falling bus fall to the front of it?
Added terminal velocity
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awarded  Good Answer
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comment Does a person inside a falling bus fall to the front of it?
@user121330 yes thanks. That's what happens when you add to an answer without reading the whole thing again. Fixed.
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revised Does a person inside a falling bus fall to the front of it?
added 94 characters in body
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comment White Noise Generator Through Low Pass Filter - Autocorrelation of normalized data dropping below 0 (showing negative correlation)
It doesn't matter whether you use normalized data for this although I would use "raw". Multiple samples should show better if there are deviations from white noise. This is definitely a strange puzzle. When you have more data please update your question with all the details - and stripping out stuff that does not matter. It gets hard to follow these things otherwise.
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comment White Noise Generator Through Low Pass Filter - Autocorrelation of normalized data dropping below 0 (showing negative correlation)
Is it a commercial device with known characteristics? What does its autocorrelation function look like without any (intentional) RC filtering? How about the Fourier Transform? If you ran 1000's of samples, calculated the power spectrum (FFT * complex conjugate of FFT) and then summed all those power spectra, you should end up with a flat (bumpy, but no structure) line. Do you?
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comment Does a person inside a falling bus fall to the front of it?
@Alchymist - that is an excellent point: Isaac might have started falling while the bus was still supported. The bus did take a long time breaking free from the bridge as it pivoted close to the center (dramatic tension - cue music). That would definitely give him a head start.
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awarded  Nice Answer
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comment SHM by using cos equation
What do you mean by the mid point? Deflection = 0 or deflection = half max?
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comment Does a person inside a falling bus fall to the front of it?
@BenjiWiebe in the movie clip he hits the window long before the bus hits the water
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comment SHM by using cos equation
@KyleKanos of course! Slaps forehead.
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comment SHM by using cos equation
Are you sure your equation is acos and not cos? If it's cos (as I suspect), you know that $\cos\theta=0$ when $theta = ...$. So $\omega t + \pi/6 = ...$ - solve for $t$.
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comment Diffuse laser light in a surface
If you have an old (dead) laptop, you will find there is a diffusing screen behind the LCD (part of the back illumination). But I don't know how to take it out without breaking...
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comment Does a person inside a falling bus fall to the front of it?
@MikeDunlavey - you gave me cause to revisit my answer. And yes - the terminal velocity of this bus is 95 m/s (with my assumptions) which means that an object (passenger) will not fall to the front in the time it takes to drop the 60 m. Actually it really drops a bit less than that - the front hits the water before the center of gravity dropped 60 m.
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revised Does a person inside a falling bus fall to the front of it?
added 1408 characters in body
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answered Does a person inside a falling bus fall to the front of it?
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comment How much UV light do we have on the ground?
The answer to this will depend on the time of day, and whether there is cloud cover... UV as fraction of daylight changes. Not sure what "as bright as just before the sunrise" means either. 30 minutes before sunrise in Helsinki in summer the sky is bright; in Jakarta it would still be solid night...
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comment Kinematic Motors in series to flywheel calculation problem
This is a pretty confusion question as written. I would recommend a few changes to make it easier to answer: 1) add a diagram, 2) create variables for rate of rotation of platform and flywheel, 3) ask a "clean" question. I think your question is "when the two motors rotate in opposite directions, it appears that the energy required for motor 2 to get up to speed is less. Why is that, when in the frame of reference of that motor all it's doing is spin a disk up to a rotational velocity of 100 rpm? Is my reasoning wrong, or is there some physics I dn't get?". Is that in fact your question?
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reviewed Leave Closed Particle annihilation - mathematical description, equations governing it?