I've played airsoft like this for a few years now off an on so feel well enough qualified to comment.

It's largely a matter of range. Most sites allow up to 500fps on snipers (and some american ones go up to 800 or so I believe), but they have a minimum engagement range (usually about 25 meters, presumably more for the silly american ones).

Basically, non automatic sniper rifles are allowed to be significantly more powerful than the 330fps (400 in some countries) other weapons are limited to, but as a result can't be used at short range (that's what pistols and compact SMG's are for!).

If you are close to the minimum range limit and it hits unprotected skin, they sting really badly, enough to draw a little blood sometimes. It's not entirely dissimilar to being whipped by a wet towel, excruciating for about half a second then it tails off to just stinging and swearing.

If it hits your vest, glasses, hat etc. then it wont really hurt at all (but you still felt it you cheating bastards! ), likewise if you are out beyond 50meters or so as the power drops off with range as you'd expect. (My brother can sometimes make shots out to 70-80meters with a VSR but you can barely feel it)

Shoot at point blank and your target can be forgiven for walking over and punching you in the face....right after they stop swearing and get up off the ground. (entirely possible to penetrate exposed skin at that range)

In practice though, trying to storm a building/room vs automatic rifles etc. tends to be far more painful an experience than being sniped. Unless that is someone snipes the inside of your nose sideways on (it hurt as much as you imagine it did).

We also once had a guy knocked clean out by a grenade launcher to the face at point blank . But it was a Co2 powered thing and I believe they aren't allowed inside buildings any more (can't think why).

Re: paintballs, in my much more limited experience, they are waaaaay worse than BB's if they are full power and reasonably close range. Concussions, broken bones and broken skin are all entirely possible (though not likely), but bruises and welts are basically standard issue.

I believe some sites run compressed air guns (rather than Co2) at much lower power levels, so I imagine they are a lot more tolerable.
Paintballers tend to be more on the extreme sports side of things (wheras airsoft tends to be more biased towards military geeks/gamers), and so many sites have a bit of a "pain is weakness leaving the body" attitude to power levels.

In the UK at least the velocity limit for paintballs at competition level is 300fps, for most airsoft sites the limit is 330fps. You only have to look at a BB vs a paintball to see what a discrepancy in energy that equates to!!!

I wonder how long the seal between the barrel and drum holds.
With your normal household revolver the gasses escaping from there are quite dangerous, scaled up to a shotgun shell wouldn't want that so close to my face.
That being said I undertand the burn velocity of the propellant is probably lower than that of a revolver cartridge, but is it significant?
Any Videosift Munitions/Firearms expert wanna school me a bit on that?

AFAIK, photons have mass, but in a theoretical state of zero velocity they theoretically don't have mass (which can't currently be tested).

As for neutrinos, I said, "at or faster than the speed of light", not "faster than the speed of light". I never claimed they do go faster than the speed of light, because the jury's still out on that one. This is still a debate that divides the physics community and the matter is far from settled.

It could be, although it's exceedingly difficult to find any meaningful numbers for distances that aren't terribly vague, and what you do find is almost always for something other than karts (semis, F1 racecars and bikes).

I still think that the open, small, only semi-streamlined form of the karts would tend to make the effective distance less than what we saw in most of this video. The lower speeds than F1 cars would tend to improve the slingshot tactic, since the effect of wind resistance increases with the cube of velocity. Which again, doesn't seem to explain the drastic slowdowns when they're not at top speed anyway.

I'm going to assume that this is the Lorentz force, because it's the principle that involves magnetic and electric fields. But there are setups that can use subtleties of magnetic and electric fields, it can be very complicated. Any physicist rather than astronomer might be able to explain this better... or spot subtleties.

If you notice, it only starts moving once the back magnet has touched the wire. Which i think means that the wire is used to carry the current from the battery, with the magnets providing the magnetic field for the Lorentz force to drive the train. Effectively the force is felt by the electrons travelling in the wire (F = q(E + v x B), x being vector product, cross product), but there is an equal and opposite force to be felt by the 'train'; so it travels along. If you watch, it does look like the wire is responding - i'm pretty sure the small track would have shot off to the right if he hadn't held it, and it moves as the train approaches in the longer track.

So, circuit is set up by the the wire contacting between battery terminals, current flows in a circular fashion (mostly, assuming adjacent loops don't short). Magnetic field will emanate out from the battery on average radially, i assume (this is a simplification but a reasonably safe one), so the resulting cross product - and therefore direction of the force - acts along the remaining perpendicular direction to those, ie. straight up or down the loop depending on which terminal is leading.

If you want to see how that works, you can use the right hand rule. First finger is the direction of the electron's velocity (which is traversing loops so constantly changing in a circular manner), middle finger the direction of magnetic field which always comes out radially from the middle of the coil or track, thumb F the resultant force always points along the loop - make your first finger point in all directions of a circle, keep your middle finger pointing radially out relative to your first finger, and you will notice your thumb always points the same way, no matter how v changes circularly.

It is reasonable to assume that other factors are involved, probably a current is induced into the coil as the battery moves - the battery carries a magnetic field cos of the magnets, so we then have a moving/changing magnetic field in the presence of a wire; it should induce a current which would create a magnetic field in opposition to the field of the magnets.. and so on. But i think the Lorentz force is what provides most of the motion.

Doesn't this belong on the WTF channel?

I know that's what I was thinking through most of this.

E=MC2 is inaccurate anyhow, and even when the equation is fixed it still doesn't describe all types of particles at all velocities accurately.

Gravity still exists, and exerts exactly the same force on you independent of whether you are standing on solid ground or falling, and whether you are falling inside an elevator or in empty space. The difference is the opposite force exerted on you by the ground vs no opposite force (except the tiny force exerted by air if you're freefalling in the open air). It is this opposite force you 'feel', while acceleration due to gravity without any opposing force feels like floating.
So a man in a free-falling elevator in an atmosphere WOULD feel a tiny bit of gravity, because the outside air would slow the elevator to less than terminal velocity, so it would slow down slightly, unlike the mans descent, making him fall/float to the floor of the elevator eventually and then feel a microgravity exactly equal to the force exerted by the air.

Yes. The animation on Yennifer casting that kickass churning earth spell thing was super wonky. Its almost like they didn't mocap the whole thing! At least get some video or something from real sorceresses casting real spells from the real world for comparison.

But srsly. I've no idea where you are seeing all this animation fail. It looks fine to me. I've also got no idea how you can criticise the plot of a game from its trailer.

Disclaimer: I am a human with 26 years of experience being around other, animated humans. Although, in fairness I have never witnessed either a horse being beheaded on the charge with a single swipe of a zweihander (I should also mention I have never witnesses a horse at any velocity being beheaded with anything), or any witches, mounted or otherwise (at least to my knowledge), but at neither of those points in the trailer did I think, "Wow, that's so unrealistic". I suppose the reason is that when I clicked on a video which was quite apparent as a trailer for a videogame, I may have prepared myself by suspending some of my disbelief.

ps. I am hyped for this game. The first 2/3 of the Witcher 2 were great.

Degeneracy is really, really cool. It's all about squashing things into as tight a region of space as you can. It's an observable justification of Heisenberg's uncertainty principle and the Pauli exclusion principle (the one that says you can accurately measure the position or the velocity of an object but not both and the one that says that two neutrons -in this case- can't both occupy the same very small region of space).

To be a neutron star, the remnant core after an unstable giant blows its outer layers away has to be more massive than 1.44 solar masses, but anything bigger than about 2.5 solar masses probably becomes a black hole. On the less massive end you get white dwarfs which are prevented from shrinking any more by electron degeneracy pressure - electrons won't let the star get any denser. But if you throw more mass on it, even electron degeneracy pressure can't resist the gravitational force and you get a neutron star, supported by neutron degeneracy - the neutrons won't let the star get any denser now. And then finally more and more mass and it becomes a black hole, which is where even the neutron degeneracy pressure can't sustain the gravitational force.

I mean, that's fucking cool - there is so much gravitational force that the electrons have to team up with the protons to become neutrons, because neutrons can get slightly closer together. And then if the neutrons aren't happy, you've got a singularity which is a fancy way of saying we don't know what the hell just happened but stay away from it if you like being in the part of the physical universe that kinda makes sense to us.

There's also speculation of a quark degeneracy state beyond neutron degeneracy.

It's probably not as bad as you think. Fish are aerodynamic (hydrodynamic?) so they would probably enter the water nose first no matter how they started out. Their tails dragging more, and forcing their heads downwards. Their terminal velocity is also very slow being they weigh so little. Pelicans dive into waters quite a bit faster than these fish would fall, and they suffer no ill effects.

I haven't done any studies, but considering how much it would cost to outfit a plane like this and fly around fish-bombing, I would think they figured out if the fish would survive or not.

Good example of why rail guns that fire projectiles at 7x the speed of sound are so effective. It's as if the energy of impact had something to do with velocity. I bet there's an equation for that.

Agree ChaosE. And show the formation in stellar light, (like god intended, haha), not gas velocity or some such.

If you have a look at this picture, the rock seems to be falling at a constant velocity, as it should if it was a meteor fragment - it should be falling at its terminal velocity.
It's hard to judge distance and speed, but might be falling at - say 1-2 meters per frame. If it is shot at 25fps, this would mean that it's falling at 25-50m/s (90-180 km/h, 55-110mph, 80-160 ft/s) faster than the parachute jumper, and would be very close to a probable to the terminal velocity of a falling rock.

I retract my earlier statement.

i think wind resistance would eventually slow it down to the point of just having max freefall velocity for it size and weight. It wouldnt continue to go 10's of thousands miles an hour in our atmosphere, it would burn up from the friction.

I'm not sure why you say that it didn't go much faster than the jumper. It only stayed in the frame about 1/3 of a second even though it's not really that close. It may be slower than you might expect a meteorite to be going, but if it's a fragment from after the disintegration/explosion of a larger one it easily might have slowed to just terminal velocity, which seems about right to me from the video.
What made me wonder was the lack of any visible smoke/trail. It could just be a rock dropped from the plane above, even a real meteor dropped from the plane (in case someone found it before the jig was up that it was faked). True, it would be a lot of effort for little pay off, but people do dumber things.
Still unsure...1/2 expecting this to turn out to be a commercial...but for what?