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ARS

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Posts posted by ARS

  1. Does the flight trajectory of an object is affected by the rate of acceleration and how the atmospheric drag behaves during the flight? For example, there are 2 projectiles launched into space at suborbital trajectory. Both has the same delta-V, same mass and same angle of launch. However, projectile A is launched normally using rocket engines while projectile B is shot using mass driver. In this case:

    1. Projectile A has a gradual acceleration to max speed and atmospheric drag that steadily rises as it flies through atmosphere before it finally reached space

    2. Projectile B has instantaneous acceleration to max speed and the atmospheric drag is instantaneously jumped to max before it finally reached space

    Assuming these 2 have the same delta-V (but different flight characteristic), does the trajectory produced are identical to each other?

  2. If I want to break the speed record, which one of these environment that would put the most and the least strain on the vehicle at high speed? (ignoring the difficulty of attaining high speed in that environment, assume we can go as fast as we want)

    -sky: flight speed record (vehicle only interact with air)

    -ground: land speed record (vehicle interact with air and ground)

    -sea surface: sailing speed record (vehicle interact with water and air)

    -underwater: submarine speed record (vehicle interact only with water)

  3. Just now, monophonic said:

    I am going to have to refer to @JoeSchmuckatelli here - he linked you to a 750W offering so I would start from there. The key is the amount of clean power the PSU can output - an expensive quality 750W PSU might outperform a cheap-o 1000W unit. But I haven't built a computer in this millennium so I don't have any relevant experience to help you further.

    Alright, thanks for the answer :)

  4. On 3/14/2022 at 2:48 PM, monophonic said:

    I would go with what @JoeSchmuckatelli said for starters. By googled numbers your voltage stabilizer should be perfectly fine. However your graphics card alone is capable of exhausting the "pure power" rating (whatever that means) of your PSU and any distortions in the output can really do a number on computer stability. A higher rated PSU would give a reasonable margin here.

    I would be extremely wary of increasing house voltage without knowing the quality of wiring you have in your walls. On the same thought if your computer is capable of significantly pulling down the voltage I would be worried about the wires condition. Are you on a national power grid or does your electricity come from a small scale solar or other setup? Is your wall voltage on the 110V or 230V range? What fuse value (amps) do you have for the circuit in the house electric cabinet?

    As @StrandedonEarth said a UPS basically functions as a voltage stabilizer too. So don't use another stabilizer with a UPS unless you need one to protect the finer electronics a UPS has. Since your computer didn't just fizzle out when you used it without the stabilizer that shouldn't be an issue.

    I am planning to buy a new PSU, should 650w enough? Or should I go higher?

  5. 26 minutes ago, monophonic said:

    If you could post some links and/or information about the equipment in question

    Thanks for the response. Here's my spec:

    Spoiler

    -Processor    : Intel Core i7-3770 @ 3.40Ghz - @ 3.90Ghz
    -OS        : Windows 7 64-bit
    -RAM        : 16GB

    -GPU        : NVIDIA GeForce GTX 750
    -HDD        : Barracuda 1TB + Barracuda 500GB
    -PSU        : Nero 225 (max power: 500w, pure power: 225w, high range voltage: 170v-240v)

    -Stabilizer    : Matsunaga SVC-1000N (output 110v-220v)

    I'm still thinking whether I should:

    -Increase house voltage to reduce the margin of power fluctuation

    -Buy a voltage stabilizer with higher range of power output

    -Buy a UPS (should I use UPS and Stabilizer at the same time?)

  6. Guys, I need some help
    So I recently bought a PC for my 3D print design and modeling need (because my laptop are no longer sufficient). It's a mid-end computer, and it did it's job properly, however, there are things that's bugging me since I used it. So, the electricity in my house is kinda unstable (but still sufficient), with the voltage frequently rise and fall erratically. Here's what happen:
    1. At first, I plugged the power cable of the PC directly into wall socket. The result is, everytime there's a power fluctuation, the computer just freeze, that is, the cursor disappear, any sound stopped and the screen just freeze in place with no way to recover it, necessitating a hard restart
    2. Then I bought a voltage stabilizer to at least make the power flow consistent (that was the only conclusion I can gather). The result is, yeah, everytime there's a power fluctuation, the PC no longer frozen in place, as the stabilizer whirrs to stabilize the voltage. However, now it exhibit an annoying habit: Everytime I worked on it, especially those that involves heavy rendering of 3D objects on screen, or doing something intensive that requires heavy GPU use, the PC frequently start to just turned off (screen goes black) and then restart on it's own (without me touching the buttons), often, such event are accompanied by a soft screech from the voltage regulator (p.s the regulator output is 220v, and my PSU range is between 170-230v)

    Should I increase the power voltage in my house? Is it the problem with PSU? Should I bought UPS?
    Thanks for the answer, I know this is not a tech support forum, but I'd like to hear your thoughts about it

  7. If the outer space treaty said that space isn't really owned by everyone, if colonies are built close to each other, let's say colony A and B are built in such a close proximity, does colony A still have sovereignity claim to what's inside their colony? That is, inside their pressurized structure area, not the soil outside where inhabitants from both are free to place anything outside with no such things as territorial border

  8. 36 minutes ago, K^2 said:

    The only situations where it's just a bad idea is if you are either trying to build a light aircraft that's controlled directly by the pilot without any stability assist, because such aircraft would be too unstable to fly safely, or if you are building something that's meant to go really, really fast, and you can't fit the canard of adequate size within the innermost...

    Ah I see. Thanks for the answer :)

  9. 120px-Pit_maneuver.svg.png

    In a typical scenario of PIT maneuver during police chase, the pursuing police vehicle rams the target vehicle's sides rear from the rear (cars are typically heavier on the front, while the rear is lighter), hopefully to make the target spin out of the control by using it's heavier front as a rotation point. Now, if we take this occurence in an ideal scenario, taking the physics into account, what would happen to the target vehicle and the police vehicle if:

    1. The target's rear is as heavy as the front (no lighter or heavier side)

    2. The target's overall weight is much heavier than the front of police vehicle

    3. The target has a rear mounted engine (meaning the rear that's getting rammed is the heavier side while the front is the lighter side)

  10. Is it possible to have a nuclear thermal rocket with the engine design that have adjustable thrust level and effiiency in the atmosphere? high-thrust low-efficiency at low altitude before gradually switching to  low-thrust high efficiency at high altitude, by adjusting the nozzle diameter and the level of fission heat? For high thrust-low efficiency, the nozzle diameter becomes smaller while the fission heat level increases (yielding high gas pressure in the chamber).  For low thrust-high efficiency, the nozzle diameter becomes larger while the fission heat level decreases (yielding low gas pressure in the chamber)

  11. At which point for a high speed projectile starts to be faster than the eye? Or more appropriately, faster than the brain can process? For example, you're viewing a blank white background, and then a projectile pass before your eyes. How fast the projectile have to travel before it starts unnoticeable by human eye? Does it have to travel faster than the speed of electrical impulse of optic nerve? Or is there lower/ higher speed for such phenomenon?

  12. 1 hour ago, DDE said:

    (1) two-stroke diesels are more difficult to miniaturize, or are too deficient at specific power for military use - contraindicated by attempts at their use in aviation

    Probably because on aviation application, the stress on the engine itself is far less compared to being used for maritime application. Looking on Junkers Jumo 205 application history, it's mainly used on slow-moving aircraft (either bomber or patrol aircraft), and their speed is considered slow by today's standard. Pushing a fuselage through air is less demanding than pushing a hull through water (not to mention the air itself helps lifting and maneuvering the aircraft). IT COULD be miniaturized, but I think it would have shorter lifespan compared when being used as aircraft engine because of higher stress in maritime application, and as a result, more replacing/ repairing the engine, which is not economical on the long run

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