Sisyphus

Yes. You should get used to thinking about velocity only relative to something specific. There is no such thing as just "moving." "The person is moving in the opposite direction." Relative to what? Not himself. Not the gun. Not the train. Let's give numbers. The train is moving at 100m/s relative to the ground. The gun fires bullets at 500m/s. A bullet fired from a gun that is not moving relative to the train will always be going 500m/s relative to the train and anyone on the train. To someone not moving relative to the ground outside, the bullet will be moving at 600m/s if it is fired forwards, or 400m/s if fired backwards. Or think of this: the train is moving at 500m/s relative to the ground. Someone on board fires a bullet towards the rear of the train. To that person, the bullet flies normally. To someone standing outside, the bullet doesn't move at all. It just falls straight to the ground, while the train rushes by under it.

There is no one measure of "destructible." It all depends on how you're destroying it. There is hardness, toughness, compressive strength, tensile strength, shear strength, etc. There is also different ways of measuring each of these things. For example, titanium is stronger than steel per unit mass, but weaker per unit volume. A titanium bar will be lighter but thicker than a steel bar of the same strength.

Well, that's incorrect. The gun gives the bullet an acceleration relative to the gun. It doesn't care what the ground outside is doing. It doesn't care that the Earth is spinning or going around the sun, which is itself moving through the galaxy. It doesn't matter whether you consider the ground outside motionless and the train moving, or the train motionless and the ground moving underneath it. The physics works exactly the same. Yes, that's what I meant.

A bullet fired on the train will have normal muzzle velocity relative to the train. Relative to the ground outside, it will have normal muzzle velocity plus the train's (and gun's) velocity.* *Not 100% true because it disregards special relativity, but for velocities as small as those possessed by trains and bullets, it's an extremely close approximation.

No, because the football and the player have been accelerating along with it. If they're all falling together, they appear weightless, and nothing happens when the player lets go.

The situation would be the same.

I would support an effective end to the War on Drugs. If it's "defeat" we're worried about, we can declare a War on the War on Drugs, then end it and declare victory. That even Fox News is critical is a hopeful sign, I guess. Though I guess they're prone to push Wasteful, Incompetent Government stories when Democrats are in charge (though this is obviously a bipartisan problem) and mention Czars, and I wouldn't be surprised if the very next segment was some hysterical piece about Drugs in Our Schools Leads to Sexting or something. But anyway, yes, hopeful sign. Public perception is the most important thing, since the only thing is based on irrational public perceptions anyway.

Right. Omnipotence and the Principle of Non-Contradiction can't both be valid. Wait...

If god is all powerful, he can microwave a burrito so hot that even he can't eat it. But then, he's no longer all powerful. I guess that god doesn't exist.

It won't hit the floor as long as the elevator is free falling - the elevator and football will just accelerate at the same rate, and everything inside the elevator will appear to be weightless. However, realistically the elevator will have a relatively low terminal velocity, pushing the air in the shaft out of the way, while the football will experience very little air resistance, since its surrounding air is carried with it. It will fall faster and reach the floor. And of course, it will definitely hit the floor once the elevator reaches the bottom of the shaft.

Only the first two options are "aliens," no?

This one. And by "lose" it should be noted that whatever is lost doesn't just disappear - it is ejected. So for example, the nucleus of carbon-14 has 6 protons and 8 neutrons. One of the neutrons breaks apart into a proton and an electron, and the electron is emitted, leaving behind 7 protons and 7 neutrons: nitrogen-14.

Maybe. Like seemingly everyone else, I guess I'm not quite sure what this poll/thread is really about. Perhaps a better way to phrase the question would be to ask, individually, how likely each of those scenarios are. As in, How likely is it that some UFOs are actually the vehicles of travelers from another star colonizing asteroids? Etc. The "assuming they are real" thing makes it hard to answer, since "they" and "real" are not really defined. But certainly we can all agree that people see things in the sky that they can't identify, so it is literally true that "UFOs are real." I can look up at the sky and see one now (though "an airplane" is a pretty safe assumption for what I'm looking at, I think). Also, my way takes into account the fact that those poll options are not actually mutually exclusive!

What is that evidence?

There's really just three reasons. Empathy, "self-worth," and external personal benefit. Empathy - Unless you're a sociopath, you have an aversion to hurting other people. This will make "doing the right thing" automatic in most instances, the default position. You hurt yourself by hurting others. You want things to be the best for everyone. "Self-worth" - Even if you don't care what happens to other people, you still want to be a "good guy" yourself, and be intellectually consistent. You would think less of someone else if they did it, so you don't do it yourself. You want to be a better person, and that includes acting ethically and morally. External personal benefit - Basically, avoiding external consequences that negatively affect you. This includes punishment, the bad opinions of others, and the "religious answer" that you will always be "caught." None of these things need be a conscious choice. Most of us aren't consciously choosing not to shoplift every time we go into a store, but we don't shoplift anyway, because these things are automatic. Also, I guess some people follow "the rules" just because they like rules. May as well acknowledge that side of it, as well. I'll also add that the question itself seems biased. You need a specific reason to do the "right" thing, but you don't to do the "wrong" thing? Why?

So there's no evidence of Neanderthal DNA in sub-Saharan African populations? How is that possible? Surely the populations of homo sapiens couldn't have been that isolated from one another, that Neanderthal DNA couldn't have spread to all populations in the timeframe of tens of thousands of years? Moderator note: Please limit political discussion to the politics forum.

I can think of a few allegorical interpretations of "the fall." Like, with the ability to reason comes the responsibility to be moral, and the burden of inevitable failure. Eating the fruit could be the intellectual awakening of adulthood, or even of the evolution of higher mental processes. Yeah, I know, none of the details really fit. I'm being generous. You could say it's mostly a fanciful tale designed to just convey that one main idea, in a way illiterate nomads might grasp. Or something.

I'm reminded of the joke about the puddle marveling how the hole he's sitting in is exactly the right shape to hold him. Remarking that the universe seems perfectly suited for us is almost tautological - if it weren't, we wouldn't be here to remark about it. Perhaps something else would. Perhaps there are, in fact, countless universes, so the existence of any with particular traits is all but guaranteed. And perhaps there are very good reasons, not yet discovered, that our universe has the structure it does. I see no reason to invoke hand-waving explanations like "God" when the real answer is "we don't know yet." Don't just assume lightning comes from Zeus because it's all you can think of. Actually investigate it, and if you haven't figured it out yet, be comfortable saying "I haven't figured it out yet." Also, surely a conscious being capable of forming a universe to suit its purposes existing "by chance" is necessarily even more improbable than whatever it might choose to create. Invoking "God" as an explanation for "fine tuning" simply adds a more difficult layer to explain, so even as a hand-waving explanation it makes more difficult, not less.

Both of those are false statements, as there is no such thing as "pure energy." It is a property of things, not a thing itself. When matter and antimatter meet, they are "annihilated," and new particles are created, like high-energy photons. If the term "pure energy" is used, electromagnetic radiation is probably what is intended.

We are in the midst of a mass extinction caused by the population explosion of homo sapiens and the development of civilization, which is expanding and changing at an accelerating rate. Trying to predict the state of the human race 1000 years from now is pointless, let alone a million, let alone five billion. The only thing you can really say with reasonable certainty about such unfathomable timescales is that nothing will be recognizable.

So he's wondering whether 'tis nobler in the mind to suffer the slings and arrows of outrageous fortune, or to take arms against a sea of troubles, and, by opposing, end them? More specifically, the question of what is the benefit of appreciating happiness is a strange one. How else would one define "benefit?" As for "whether it all matters," I personally just say that "it" has what meaning we give it, so if "it doesn't matter," one has only oneself to blame. And of course, no rational argument is going to be a quick cure for teenage intellectual awakening and the inevitable accompanying cynicism, angst, and ennui. Though sometimes it can help. As an angsty teen myself I got into the philosophy of Albert Camus, which provided a satisfying (to me, at the time) answer to what "the point" of it all is, as well as appealing to my rebellious sensibility. The important book was The Myth of Sisyphus. (The username is just a coincidence, BTW.)

That's exactly the point - it isn't a pump mechanism. And the system has less potential energy in it when the wick is filled with water. There is no way around it.

I'm not talking about losses. I'm talking about getting more energy out of a system than you're putting in, which is always impossible. With the chemical idea, you're essentially just using that chemical as fuel. With a vacuum, that's going to take more energy to produce than you can generate using it.

It won't work like a neverending pump, because capillary action is not an input of energy. It's passive. If the capillary action gets a certain quantity of water up a certain height (giving it potential energy), then it will take more than that amount of energy to get it out of those tubes. Think of it like a magnet - you can extract energy from the force pulling two magnets together, but then you have to use more than you extracted to pull them apart again. Capillary action is the same thing, just with the adhesive forces between solids and liquids. Water up in the tree is actually the lowest energy state, despite the additional gravitational potential energy, because you've used up the potential energy of the intermolecular attractive forces. A tree can keep sucking up more and more water only because there is an energy input - the sun - evaporating water at the top, making room for more water, etc. Like if you had a chain being pulled towards a magnet, and every time a new link touched the magnet, you pried it off. It would keep pulling the chain, but you'd have to keep using energy to pull new links away. In short, you can't ever get more energy out of a machine than you put in.

That picture is begging for a caption contest.