Mr Skeptic

Well if you know calculus, you don't need to remember how to get energy from the force for each particular circumstance. You just need [math]W = \int_{x_0}^{x_f}F \cdot dr[/math]. That will give you the energy regardless of what the force is or how it changes. For the above problem, you are essentially given the result of the integration for the force of friction and the spring force.

Ah, if there is no permanent damage then I guess it's OK. It's just that the machine described probably would cause major dependence problems. http://en.wikipedia.org/wiki/Pleasure_center#Experiments_on_rodents

So then you can choose to prefer men over women? I know you can chose who you go to bed with, but most people want to do so with someone they find attractive. Can you control your heartbeat too? That after all is an action. It comes from a retrovirus that infects and kills off white blood cells. Now you know.

Nah, I just use google to find stories on a topic I'm interested in.

How would you like it if someone gave you so much pleasure that it burns out your dopamine receptors and you can't feel pleasure again without hitting a switch?

Google.

Depending on how much they do it, it could be far worse than normal torture. This is little different than turning the guy into a drug addict and then offering them drugs in exchange for information. Only far stronger but without organ damage from metabolizing drugs.

I assume you don't know calculus. It would be convenient for this problem but you can do it with constant force and knowledge of potential energy instead. The force of a spring is -kx where x is the displacement from equilibrium and k is the spring constant. The friction of the barrel is constant, so at the start you have both the force of the spring and the friction acting in opposition. The energy loss from friction is F*d. The potential energy of the spring is (1/2)kx^2. First, find the displacement at which the force of the spring equals the force of friction. Next, take the starting potential energy and subtract the potential energy at this point, and the losses from friction at this point. That's your maximum kinetic energy, from which you get the max speed. Then add to this the remainder of the potential energy and subtract the remainder of the friction losses (or subtract the whole friction loss from the whole initial potential energy), and that gives you the kinetic energy at the exit.

Don't all waves carry momentum?

I think the best solution is this: Make drugs legal to buy, sell, and use in private. Tax the drug sales, and use the money to fund rehabilitation and education programs. The tax should be low enough that it is not worth it to sell illegally to avoid it. Have it be illegal to sell on public property, and to advertise or "push" drugs.

Farsight, if your space is non-flat, then I don't think you can count on the volume being the integral of the surface.

Rehabilitation is better then throwing them in jail for it, for sure. It's definitely a reasonable compromise.

Sort of. It's more a unit conversion. Kind of like if we measured "up" in inches but "forward" and "sideways" in meters, then you'd have a unit conversion between "up" measurements and "sideways" measurements. I suppose you could call that the "length of up".

Some random, perhaps impractical ideas: I'd go with, a forum that uses tags rather than subforums for classification, with each tag also being in the more general classes (eg global warming would be in politics and meteorology and environmentalism). It could have several tags, even very highly specific ones. You could set it up to give a priority bonus to tags you are interested in, so interesting stuff is visible, and also the computer should be able to make some good guesses as to which topics interest you and put those threads near the top. I'd have several options for the general structure of a thread: it could have the posts nested by which post they reply to, or chronologically, or it could have a poll, or it could have a wiki of sorts at the top, or perhaps a summary of the main points made during the debate, and an optional experts-only mode. Ideally the moderation could be mostly done via crowd in a way that can affect the visibility or prominence of good posts. The system could analyze the sort of posts you like to see and make those more prominent for you personally People could make groups (eg by expertise) and exclude non-members from posting (but not reading) on certain experts-only thread, allowing certain topics to be discussed without crackpots, fanatics, Einstein wannabees, or distractingly ignorant folks distracting. Just for certain topics, or for the folks who want to have a highly technical discussion without having to explain stuff to random people.

A good idea, but how can we measure the efficiency of things, and the efficiency improvements that the official does? If we could do this, we could kick out the ones abusing their position. If we can't, we can't pay them based on this number.

The trouble is there are multiple possible interpretations for that. For example, it could mean that the atmosphere is protected from being damaged, so that we can't pollute it. It could mean that we can't "climb" the atmosphere, ie fly. If someone says something vague enough then there is almost certainly an interpretation that happens to be true. The Nostradamus folks do this all the time; fortune tellers do it professionally.

At what point does the force the spring is applying become less than the force of friction on the projectile?

Bullets are supposed to be slightly soft. Making hard bullets you might explode your gun, have some hot gasses leak around the bullet, and/or cause increased wear on the barrel.

Heh. Well first of all, you need your energy input to be more than the synchrotron radiation. Synchrotron radiation is proportional to the acceleration, which depends on the radius, so with a larger radius you reduce this loss. There's probably other reasons too. The accelerator accelerates particles in bunches. There needs to be activation of the accelerating components in a sequence moving at very close to the speed of light. I'm not sure what size is necessary for this. There's a limit to the sort of fields a material can hold before being destroyed. I recall hearing about a system to induce an electric field in a plasma via microwaves because it could make a stronger field than the best solid materials. The stronger the fields, the smaller you can make your accelerator. Merged post follows: Consecutive posts merged Yes. When you accelerate a charged particle, it emits EM radiation.

Hm, it would make some sense for the brain to consider insulin a "reward chemical" of some kind. Increased insulin generally means you ate a good meal, and you should remember what you did to get it. No?

Actually, adding any solutes lowers the freezing point of water. Salt works particularly well since really you are adding both a Na+ and a Cl-. Freezing point depression is a colligative property.

I think you can reduce insulin by lowering blood glucose (assuming the body is functioning correctly).

Well, gravity can indeed destroy objects, and it doesn't need to be a black hole to do so. Tidal forces can break apart planets that are too close to another massive object. Now as for your astronaut, the problem is not that gravity is pulling him, so much as that it is pulling in different directions and at different strengths. You get shredded. The technical term for this is spaghettification. The time dilation effects depend on how deep in the gravitational well you are; the spaghettification depends on how "sharp" the gravitational field is. Essentially this means that if you have a large enough black hole you should be able to survive falling through the event horizon (you'll still die later though), whereas a smaller black hole will shred you before you could reach it. Now as for differential time dilation effects, I'm not too sure how it would work. I think that your legs would feel dead but act hyperactive (possibly twitch uncontrollably) due to how this would affect the nervous system. Remember that your legs are being tugged harder than the rest of you cause they're nearer. Maybe you'll see them shredded in slow motion? However I think you may be right about the flattening. Some theories say that it takes infinitely long time to cross the event horizon.

If they didn't exist, you wouldn't want to hurt them to the point of non-existence. It's a paradox! Adding people to your ignore list works pretty good too.

Well I can tell you that the military don't take kindly to the possibility of their critical equipment being wiped out in a single attack. Military hardware is specifically hardened against EMP weapons. Of course a strong enough EMP at close enough range will still take them out, but they have prepared for the possibility. I think also that our optical networks would survive an EMP. Anyhow, if you want some real numbers I think one of the folks at the military might be able to help you. Navy Electromagnetic Pulse Assessment Group