*wtf - that is a lot of momentum.

Well, taking into consideration that these appear to be stable and contained laser bullets, rather than beams, I think it wouldn't be far-fetched to assume that they could travel magic light years through space until they collided with magic, at which point they would likely lose some marginal magical momentum and also generate secondary or even tertiary magic. Also I guess magic.

Pole vaulted in high school. I sucked. Another guy, who sucked a bit more had his pole break in 4 pieces. His momentum kept him going into the pit so no big deal. It's not very uncommon, or at least it didn't used to be. Poles definitely have a shelf life and I'm pretty sure the policy at our school was to use poles until they broke.

I don't get how they don't fall back on the track more often than not... especially before you get to a competitive level. Several ways... not enough jump to get past vertical and towards the mats, slipping down the pole, letting go too soon... I'd guess holding the pole too long is probably bad as well, but I'd think you'd likely still end up on the mats at least, just knock the bar off... though momentum would become an issue at some point too I'd think.

It's wind resistance, it makes a massive difference. When they're really far apart the rear driver is just driving better and shaving time off the lead, so he catches up, but once there it's down to drafting to get the little burst of speed to get alongside. The carts are probably approximately equal in power, so he reaches level from the draft position easily enough, but can't keep the momentum to get a lead with the new air resistance on him, just draw level. So they're level, but obviously there's only one sweet racing line to take to keep your speed up and lap time down. You can either pass on the outside (in which case you have to go faster into the turn to stay ahead) or the inside (in which case you have to turn sharper at speed to stay ahead) both of which are risky, or you can return safely to the racing line - i.e. not by swerving into him, but by conceding the lead to him and dropping in behind him. If you do that, you take less risk and give yourself the chance to try again because you're in draft position again. He needs to stay as close as he can and find the right place to overtake so that his superior driving can give him the lead into the racing line of the next corner, at which point he gets right of way and the position advantage the lead gives. Sometimes that's not even possible and lead to what some would call boring races (Monaco Grand Prix) where the leader is decided on the first corner and doesn't change unless they crash out.

I'll draw two parallels:
1. DRS in F1 racing, where a tiny part of the tail opens up for a small part of the track, which drastically increases speed and allows for more interesting races because it almost ensures overtaking. You can also see the same application of the racing line and people conceding position or trying to take different lines and spinning out or locking up.
2. In cycling, the commonly quoted figure is that you can save 40% of your energy by drafting behind a leading cyclist. The Tour de France and every other cycling road race is defined by drafting, cos no lone cyclist would ever be able to keep pace with the peloton which 'cycles' riders in and out of the wind-protected bunch throughout a day. This should convince you more as cyclists are not streamlined objects but still offer significant gains. Go and watch a cycling sprint finish - it's a case of whoever gets behind the fastest guy wins by conserving energy in his wake until it's time to burst out alongside and pass.

Three good reasons to aim [an attack at] an opponent's sword: gain a tactical advantage (e.g. position, or momentum of either blade), gauge a reaction (e.g. is your opponent tense or over-reactive), or wear out your opponent.

Number of the films shown that do so for those reasons: surprisingly high, by my count... maybe 10-15%.

Nice montage, but I'm off to find a one of swordfights that are both artistic and realistic. There are so many good fights out there.

I'm pretty sure I only upvoted this out of pure momentum from his previous videos.

Dear non snow drivers,

In the absence of a winch, preferably a tow truck winch, this a great example of how to get unstuck.

- Keep the wheels straight, or as straight as possible. The more the wheels are turned the more difficult it is to extricate out of the stuck position.
- DON'T spin tires. They guy in the video didn't even have the car on. The more you spin, the more you dig, the more you dig the "stucker" you get. As soon as you hear tire spinning back off and try again.
- Rocking is good. The more you can gain momentum from rocking the better. It will let you spin the tires less and avoid digging the car deeper into the snow.
- Dig a trench for the tires if you can. The deeper the snow the better chance you have of catching the car on excess snow which then makes it even harder to get out. Digging trenches for the path out will help not build up snow on the way out. Foot, shovel, anything you can get to help the car out.
- Sand or kitty litter will help the drive wheels get some traction on the way out. Better yet chains will get you out of most anything, but you only usually see chains in mountainous areas or back country scenarios.
- Two words... Snow Tires (but they only make sense if you live in a temperament climate that receives snow fall, but man do they make a difference).

From the video it looks like first snow fall of the year. The tire tracks expose leaves and dirt underneath. First snow fall in my city means about 80-100 accidents in one day, its horrible. Changing mindsets from non-winter driving to winter driving is an exercise in observation and patience.

You use that word deserve. Why? Nobody is saying that. Shit happens to everybody, deserving or not. Our point is that this isn't a big fucking deal. It's just part of the shit people put up with living in a society. While qualifying it as "not as bad" you still compare it to rape. That's dumb.

The fact is she probably has it easier than every cat caller in the video. Thin, cis, rich, white woman problems don't rate. Sorry.

My concern about this video comes from a broader context. I'm a shade left of Mao, so I'm poorly represented in politics. Still, I would rather see the dems take the next two cycles. This video is embedded in a context of watching the left overplay their perceived (and previously realized) advantage with women voters. It's a transparent attempt to build momentum for Clinton 2016. People are sick of it. Polls suggest the strategy will cost them dearly in November.

I think that momentum was slowed by his head hitting the back of the car and was also converted into rotational energy which flipped him around.

There is so many factors that came together for this video though that it is either a really amazing timing/coincidence or it could be a very well setup stunt/cg demo.

Either way it looks real enough for me so call me impressed.

Agreed. While this is an effective demonstration of conservation of momentum, it is also dangerous. You need to make sure to do things safely. That is all on the professor as they are supposedly the expert and are in charge.

At around the 1:20 mark the ship starts to suddenly move screen left. There are also loud sounds. I believe the ship struck the canal on the port side, where we could not see. Forward momentum (which is massive on these ships) caused the path to divert starboard, crushing the mule. Massive ships like that barely fit through the canal, so it is critical they align straight as they enter. You can see earlier in the video that the ship's stern was much further away from the side of the canal than the bow. They simply can't enter at such an angle. Clearly somebody was in a hurry to move traffic along and ignored proper protocols.

I'm sorry mate, but i'm going to have to refute a bunch of this. And i hope i can do it without coming across as religious in my approach.

"Your "facts" are nothing but easily manipulated simulations based on theories," Excerpt from your full quote below.

-- The facts and science are not in contention and they are not "easily manipulated simulations". What we have are conclusions made by studious people based on data collected by electronic instruments world wide. The data is statistically analysed to find trends and patterns and then those trends and patterns are separately analysed to see how likely they are. When hundreds of those studies are done, consensus is formed and that is how humans come to all the theories that you adhere to every day; such as gravity, conservation of energy and momentum, etc. We then construct simulations that adhere to those theories and pass different parameters into the simulation to see what the results would be in a certain amount of time. Those parameters are the things you can change, a typical parameter might be the fractional amount of greenhouse gases per cubic metre or something like that, change in volume of polar ice per day perhaps. Thousands of studies analyse thousands of different parameter values and conclusions are drawn from the whole. That is why so many scientists now believe in climate change - because over thousands of scientific studies, the conclusions have pointed overwhelmingly and convincingly to bad news for humans.

I can't dispute your accusation that they are "based on theories". I have yet to meet a person that preferred to have their facts based on anything other than theories. A theory is a collection of ideas relating to a certain topic that are based on independent principles. The alternative is to pin words to a dartboard and throw blindfolded to construct facts. Or perhaps have a floor covered with words and let sacred chickens run round shitting our facts out for us. I'd prefer to use independent principles and the best logic we have available to us.

Please read this bit in particular
Scientists are not tricking or fooling anyone, there is no money in it for a scientist. If they try to lie, they are ridiculed by the rest of the scientists. If you spend 3 years at any decent university doing any science then you will discover that the scientific method is pretty sacred to scientists because it's the only way the field progresses.

BUT BUT BUT politicians get hold of the studies and lie to you about what they mean or how best to solve the problems they illuminate. They want your money, and they manipulate the science to get your money. They can do that because most people are not scientists, and need someone to explain it to them. So my advice is that you do not choose politicians to do that job, but instead use independent adherents to the scientific method who choose to dedicate their lives to scientific study - like Neil de Grasse Tyson who speaks as a scientist... and if he did not, his reputation within the scientific community would be in tatters, and other budding scientists like myself (and others) in this community would be highlighting just how full of shit he is.

So, are scientists lying to us, or are politicians lying to us? What seems more likely?

Cyclist here too, have been for 35 years... The most traffic laws i break involve things that stops me using the only advantage over walking, inertia. That means running on red lights is common but only if it's totally empty crossing.. People who use motors to go forward don't have to use muscles so it doesn't always enter their minds that cyclists rely on rolling forward all the time, stopping as few times as possible. That's why cyclists need to bend the rules pretty often, it just works a lot better for all of us. Of course i could stop at red lights, specially if it's button activated, i could reserve that 20s instead of using 3s making everyone wait... But here it has been a lot more common to use cycles and drivers do behave well on intersections letting that momentum to carry us over and saving time from everyone. We just can't count on it, i would say 80% do it well, it's that 20% that feels hurt if they have to yeild to a puny sack of meat riding on a tubular frame..

Last winter was brutal, instead of snow we had ice that melted a bit during the day and froze overnight. Then it was a case of survival with a bike and things from my teens started to bother me: cars that don't understand they cant tip over and hurt them selves, going thru safe, dry routes became a real fight. When i was school age, i had to to cycle on the road, with cars, no shoulder cause of snowbanks, just four deep tracks that the cars had made. The times the car horns scared me when the motorists blamed me for driving on the only piece of road i could do so, width of maybe 20cm with ice on both sides.. man., you couldn't get out of those without falling spectacularly while the cars of course could, they just were lazy. Now a days there is a cycle road built separately there but the attitude became obvious "roads are for cars, if you don't have one, stay at home..."

Durrrr.... you start your 'explanation' by saying our galaxy rotates around a central axis and momentum is conserved... ok
BUT THAT DOES NOT MEAN IT SHOULD BE FLAT.
You are starting your 'explanation' with the the presumed result.
ie. You are explaining NOTHING