There's no such thing as a reactive force, it's just an abstract concept made up by physicists to generalize the mathematics of motion.
The 'real' forces involved here are the those produced by collisions betwee molecules of matter (or indeed transfers of photons between their electrons). If you consider which of those collisions are imporant to the motion of the rocket then you'll unsderstand what I'm talking about.
I'm not saying that Newton was wrong, I'm just saying he's not telling you anything about why the rocket moves.
Nope, that's not how it works. Yes, it's certinaly a result, and the math adds up to the same thing, but it's not the cause of the thrust.
Imagine an expanding (by heat or chemical reaction) gas in an enclosed chamber. The pressure on the walls of the chamber is (mostly) evenly distributed so there's no resultant force on the chamber. If you open one side of the chamber then the pressure on that side drops to zero and the pressure on the opposite side drops in accordance with the flow rate through the open side. Molecules of expellant are buncing off the front side of the chamber, and off each other, exerting pressure on the rocket, causing it to move forward.
The conservation of linear momentum tells you that the sums should add up, and indeed they do, but they don't tell you anything about why they do.
the problem with this otherwise excellent idea is that when we eventually turn the moon into a penal colony, they'll be able to use the gun to start a revolution.
the conservation of energy is a law, it explains why things must happen, it doesn't explain why they happen.
a rocket works in space because the expanding gas exterts more pressure on the aft-facing components of the engine (including other gasses) than the bow facing ones.
In exatly the same way, a propeller doesn't move a ship forward because it's pushing water backwards, it does so because the water behind the blade is pushing forward (relative to the aft-moving inertial frame of the blade).
with a bullet in a gun, it's the expanding gas exerting pressure on the rear of the chamber that causes the kickback. of course, the intertia of the bullet governs the amount of pressure exerted, but it's not the forward motion of the bullet doing the work. That's just an effect.
You can download the 'free' Platform SDK from microsoft... It doesn't contain MFC or support for building MSVC projects, but it's got all the tools, headers and libraries you need.
That's mostly true, but as a contrast: how many prople born in the 1890's thought they'd live to see live pictures of a man walking on the other side of the planet, let alone on the moon...
Actually "half globalization", as you put it, is perfectly possible. It's called 'treaty', and they're very selective. Most countries have treaties covering such things as trade, immigration, law enforcement.
.NET code doesn't necessarily run in a "virtual machine". it runs in the CLR, which provides memory management, code execution (which may be interpreted, or JIT), and interfaces to native code among others. C compilers use an internal representation of your code and generate machine code from that internal represenation in a single stage. The.NET runtime just moves the machine-code generation stage into the process of the executable. There's no real reason why the code generated would be much less efficient than a garbage-collected C/C++ app. It also doesn't imply having a GUI, it's perfectly reasonable to write console apps in.NET using the same stdin/stdout mechanisms available to native code.
the universality of cellular automata has been known from at least as far back as when Wolfram was a toddler
can you back that up? as far as I know, wolfram was the 1st to enumulate a cyclic tag system capable of running a turing machine using an elementary 2-color CA.
Yeah, and 75% of the cost of kid's football helmets goes toward insurance. If the same thing happened to software then expect the price of software tripple, and see free software disappear when people realise thay may be liable in court for bugs they release.
Yeah, that's pretty easy to do when you control the hardware, the software and the market for both.
In the PC world it's somewhat harder to include some piece of hardware that hardly anyone's going to use when your competitor can leave it out and charge $50 less for effectively the same machine.
Gotta love the 'informative' mod on this one. This post couldn't be more uninformative if it tried.
Firstly, internally, Microsoft uses SQL Server and Exchange pretty much exclusively for their respective purposes (for both development and enterprise). Exchange is perfectly capable of handling all of microsoft's employee's email around the globe.
Secondly, if there are no MS products in use at Sun, how do you recon they develop and test their Javasoftware?
well ok, you don't have to rewrite them, someone has apparently done it for you, but my point still stands: a collection is collection, and (well implemented) generic collections mean you don't have to worry about which library you're using, you just use List<int> or List<MyType> and the compilers (build & JIT) take care of the optimizations for you.
yeah, but the whole point is that C# doesn't need to box primitive generic types, it'll just JIT-compile a version of that method specifically for that primitive type, so a <T>[] becomes an int[] (as opposed to a casted Object[]), for example. Likewise for object types, C# doesn't need to do the casting that Java requires.
Yeah, but what if you want a collection of ints? You either have to write a completely separate collection, or you have to wrap your Object collection with Integers and put (expensive) casts all over the place.
RTFA. AH is not talking about being able to pass primitive types to generics, he's talking about the JIT compiler being able to use primitive types in an instantiation of a generic. In Java all generics' type parameters are derived from Object (whether or not they were specified as such). In C#, type parameters can be unboxed primitive types and the JIT-generated code will treat them as such.
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The USPTO is fully funded by applicants, you fool.
The 'real' forces involved here are the those produced by collisions betwee molecules of matter (or indeed transfers of photons between their electrons). If you consider which of those collisions are imporant to the motion of the rocket then you'll unsderstand what I'm talking about.
I'm not saying that Newton was wrong, I'm just saying he's not telling you anything about why the rocket moves.
Imagine an expanding (by heat or chemical reaction) gas in an enclosed chamber. The pressure on the walls of the chamber is (mostly) evenly distributed so there's no resultant force on the chamber. If you open one side of the chamber then the pressure on that side drops to zero and the pressure on the opposite side drops in accordance with the flow rate through the open side. Molecules of expellant are buncing off the front side of the chamber, and off each other, exerting pressure on the rocket, causing it to move forward.
The conservation of linear momentum tells you that the sums should add up, and indeed they do, but they don't tell you anything about why they do.
no, but you can download the SDK and drop in the eval verison of intel's compiler.
the problem with this otherwise excellent idea is that when we eventually turn the moon into a penal colony, they'll be able to use the gun to start a revolution.
Oh, I should have added, of course, that lameass trolls probably don't need their SDK either.
If you don't have IE, then you don't need their SDK.
you can just get the most recent version of the compiler from the platform SDK. it'll produce better code than the version that ships with VC++ Pro.
You can download the 'free' Platform SDK from microsoft... It doesn't contain MFC or support for building MSVC projects, but it's got all the tools, headers and libraries you need.
one of my favorites
That's mostly true, but as a contrast: how many prople born in the 1890's thought they'd live to see live pictures of a man walking on the other side of the planet, let alone on the moon...
It just has a big problem convicing most of its citizens that it can afford it.
Actually "half globalization", as you put it, is perfectly possible. It's called 'treaty', and they're very selective. Most countries have treaties covering such things as trade, immigration, law enforcement.
.NET code doesn't necessarily run in a "virtual machine". it runs in the CLR, which provides memory management, code execution (which may be interpreted, or JIT), and interfaces to native code among others. C compilers use an internal representation of your code and generate machine code from that internal represenation in a single stage. The .NET runtime just moves the machine-code generation stage into the process of the executable. There's no real reason why the code generated would be much less efficient than a garbage-collected C/C++ app. It also doesn't imply having a GUI, it's perfectly reasonable to write console apps in .NET using the same stdin/stdout mechanisms available to native code.
The grandparent post may not have been new, but at least it was interesting...
Yeah, and 75% of the cost of kid's football helmets goes toward insurance. If the same thing happened to software then expect the price of software tripple, and see free software disappear when people realise thay may be liable in court for bugs they release.
In the PC world it's somewhat harder to include some piece of hardware that hardly anyone's going to use when your competitor can leave it out and charge $50 less for effectively the same machine.
Firstly, internally, Microsoft uses SQL Server and Exchange pretty much exclusively for their respective purposes (for both development and enterprise). Exchange is perfectly capable of handling all of microsoft's employee's email around the globe.
Secondly, if there are no MS products in use at Sun, how do you recon they develop and test their Java software?
well ok, you don't have to rewrite them, someone has apparently done it for you, but my point still stands: a collection is collection, and (well implemented) generic collections mean you don't have to worry about which library you're using, you just use List<int> or List<MyType> and the compilers (build & JIT) take care of the optimizations for you.
yeah, but the whole point is that C# doesn't need to box primitive generic types, it'll just JIT-compile a version of that method specifically for that primitive type, so a <T>[] becomes an int[] (as opposed to a casted Object[]), for example. Likewise for object types, C# doesn't need to do the casting that Java requires.
Yeah, but what if you want a collection of ints? You either have to write a completely separate collection, or you have to wrap your Object collection with Integers and put (expensive) casts all over the place.
RTFA. AH is not talking about being able to pass primitive types to generics, he's talking about the JIT compiler being able to use primitive types in an instantiation of a generic. In Java all generics' type parameters are derived from Object (whether or not they were specified as such). In C#, type parameters can be unboxed primitive types and the JIT-generated code will treat them as such.