J.C.MacSwell

The at rest length of each car being longer than the gap, and given the geometry shown...depending on alignment it bridges and continues or hits the other side...there is no relativistic speed at which it will fall through. It is not 100.00000% rigid but it does not lose the rigidity that it has, never mind fall (accelerate downward) like that in that amount of time.

Yeah. Slow as it was, it went from reasonably good to horrible at almost the speed of light... The train falling through the gap was especially bad. That happens (of course) in neither frame.

You have enough if you include enough simplifying assumptions, Ideal spring, massless, force is proportional to displacement. The acceleration can be calculated at any point after release and will be proportional to the force and thus displacement where a=F/m. You can use calculus to do the same wrt time.

Arguably your father was in a superposition of right and wrong... Seriously I don't think at base level there are causes as we know them...there is something unknown to us at that level such that nothing is predetermined as an inevitable cause.

We could probably make a list of what is likely to develop and be stable and what is not, to add to what Klaynos said. Orbits more or less on the same plane, same direction, spaced apart enough not to overly interfere, would I think be most typical.

I can't either...but my conclusion was a little different...I concluded my brain must be finite...

It would need negative mechanical advantage to do this quickly enough to replenish...ideally breaking even assuming no losses...so you have gained nothing prior to analyzing the losses...and are behind after you do.

That's right. ..and it would need to be identical...the first mass dropped changes the planets mass, where is the moon, etc...not that it would be a measurable difference in any case

Same speed but heavier object will hit in (negligibly) less time, if dropped at different times under identical conditions otherwise, due to planets reaction, if that is what you are getting at.

Depending on where and/or when they happen in FOR #1, their may not be that many possibilities in others. I can only picture 4 events separated in space where there could be any order in another frame. I can't see where to place the 5th so that it works in any order...though it may be that I just can't see it.

At what point in the hour + does he present this? From the perspective of the observer, the source is redshifted initially as it is sent due to time dilation, and is further redshifted by doppler effect as it is received. An observer at the source perspective of the same events would see extra doppler shifting of the unaffected signals (more than the combined redshifting above), but calculate that the receiver's time dilation would make them perceive it redshifted the same as above.

For that you must answer the age-old question: If a man says something deep in a forest without his wife around to hear...is he still wrong?

Well I guess that saves Phi's math whiz from working it out with a pencil...

So...seems urine trouble finding the terminal velocity

Eugene Wigner had similar thoughts... https://en.wikipedia.org/wiki/Wigner%27s_friend

Sorry, but I beg to differ. A physical system is something defined for the purpose of analysis, and wrt the system the CoM translational energy is always zero.

Does it add energy to the system?

I guess we have evolved a lot in the last few years then...

MigL did say system...

The coefficient of lift is just a comparison and is based on the pressure effect on the area of the wing compared to what the the dynamic pressure would be if over the same area (with incompressible flow assumed). It can be greater than 1, or even well over 2, because the wing has two sides and the pressure drop on the top side can be even greater with the wing deflecting more of the flow field than just the cross sectional area that would be equivalent to the area of the wing. I hope that makes sense...if it was just a jet of water then lift could be a maximum of coefficient of 1 based on the cross sectional area of the jet with the jet deflected 90 degrees (for drag it could be 2 deflected 180)...but can be greater in a field of flow and taking the area as the area of the wing is somewhat arbitrary (though understandable) ...and the half is the same half...though often plugged in as density/2 it is actually the same half from the kinetic energy and related to the velocity and distance as discussed in your video.

Eventually you can expect so.

...and that folks...wins this brain teaser!

Thanks. Just realized it might not be clear it was a Far Side. Always loved Gary Larson.

If you want to use u as described, and use t as n seconds, you need to subtract the distance traveled up to n-1 seconds.