Guns of Star Wars capital ships

[Surgo]

Observation: device maintains constant altitude.
Deduction: device is doing no work.
Conclusion: device is not expending energy.

I'm probably going offtopic, but this raises a question in my understanding of physics.

Maybe I'm missing something obvious here, but I don't see how you can get that deduction from the observation. Just because the device seems to maintain a constant altitude does not rule out minute oscillations of altitude over some small quantum of time (which happens in The Real World) which would be gravity pulling it down, the repulsorlift engine pushing it back up. So where the overall work done would be zero, as would the change in energy, the device would still be doing work against the gravitational field at points.

[Darth Wong]

Observation: device maintains constant altitude.
Deduction: device is doing no work.
Conclusion: device is not expending energy.

I'm probably going offtopic, but this raises a question in my understanding of physics.

Maybe I'm missing something obvious here, but I don't see how you can get that deduction from the observation. Just because the device seems to maintain a constant altitude does not rule out minute oscillations of altitude over some small quantum of time (which happens in The Real World) which would be gravity pulling it down, the repulsorlift engine pushing it back up. So where the overall work done would be zero, as would the change in energy, the device would still be doing work against the gravitational field at points.

Your car is held off the ground by air-filled tires, which undergo minute variations in height over time, or even when wind blows on the car. The same is true of the springs in its suspension. Do you believe that these devices must therefore require power?

[Surgo]

Fair enough. I thought I was missing something obvious (in this case, an example). Must be that it's just so...exotic...

[Darth Wong]

Fair enough. I thought I was missing something obvious (in this case, an example). Must be that it's just so...exotic...

One of the coolest things about learning science is that you eventually discover how to model everyday things with physics and math. Kids grow up thinking of physics as something exotic, almost as if it is irrelevant to everyday events.

[Dooey Jo]

Observation: device maintains constant altitude.
Deduction: device is doing no work.
Conclusion: device is not expending energy.

That's a pretty shaky conclusion, since you don't need to do work in order to expend energy. Just look at such beasts as hovering helicopters (which are actually doing work on the air, but not the gravitational field; but in any case, the engines are expending much more energy than the work they're doing). The official literature says that repulsorlifts don't need energy to maintain a constant altitude, but given we have no way of knowing how such a device would work, it's not a conclusion you can make out of hand based only on the observation that it doesn't do any work against the gravitational force.

[Connor MacLeod]

While you can expend energy by doing no work it will generally manifest in other ways in the enviroment (IE True Q and power generation as an example.) it does not seem likely that shields expend much of their energy in other forms. We have countless examples of shields inside an atmosphere (prequels and whatnot) and they never seem to involve radiating huge amounts of waste energy out into space. Besides that, ,a shield system that loses most of its energy as waste would be pretty ridiculous anyhow, and I imagine it would lose energy in more than just one direction (which might risk cooking the ship and its occupants if you get lots of waste heat trapped INSIDE the shield...)

Edit: The same also applies to repulsors, incidentally. Generally speaking Repulsors seem to be rather energy efficient devices, especailly considering some of the insane feats we've seen them do (the Falcon's repulsors in Rebel Dream 1000 km from a Neutron star, for example.)

[Darth Wong]

Observation: device maintains constant altitude.
Deduction: device is doing no work.
Conclusion: device is not expending energy.

That's a pretty shaky conclusion, since you don't need to do work in order to expend energy. Just look at such beasts as hovering helicopters (which are actually doing work on the air, but not the gravitational field; but in any case, the engines are expending much more energy than the work they're doing). The official literature says that repulsorlifts don't need energy to maintain a constant altitude, but given we have no way of knowing how such a device would work, it's not a conclusion you can make out of hand based only on the observation that it doesn't do any work against the gravitational force.

The wording is oversimplified. What it should say is "Conclusion: device does not necessarily need to expend energy".

[PainRack]

While you can expend energy by doing no work it will generally manifest in other ways in the enviroment (IE True Q and power generation as an example.) it does not seem likely that shields expend much of their energy in other forms. We have countless examples of shields inside an atmosphere (prequels and whatnot) and they never seem to involve radiating huge amounts of waste energy out into space. Besides that, ,a shield system that loses most of its energy as waste would be pretty ridiculous anyhow, and I imagine it would lose energy in more than just one direction (which might risk cooking the ship and its occupants if you get lots of waste heat trapped INSIDE the shield...)

Edit: The same also applies to repulsors, incidentally. Generally speaking Repulsors seem to be rather energy efficient devices, especailly considering some of the insane feats we've seen them do (the Falcon's repulsors in Rebel Dream 1000 km from a Neutron star, for example.)

Actually, we do see examples of waste heat and energy in the EU. For example, personal shields radiate light and have a bubble like effect in the prequels, not to mention Isolder personal shield has a sound.
The issue as always is HOW MUCH. Recall the debate about how personal shields and droids involve the argument that shielding may be non-economical for organic troops because of waste heat?

[Connor MacLeod]

Actually, we do see examples of waste heat and energy in the EU. For example, personal shields radiate light and have a bubble like effect in the prequels, not to mention Isolder personal shield has a sound.
The issue as always is HOW MUCH. Recall the debate about how personal shields and droids involve the argument that shielding may be non-economical for organic troops because of waste heat?

Yes, I am aware of this. Note that I was talking about large quantities of energy. as in, living things can stand within metres of a shield and not be severely burned or reduced to ash by proximity. Or cooked inside them.

[PainRack]

Yes, I am aware of this. Note that I was talking about large quantities of energy. as in, living things can stand within metres of a shield and not be severely burned or reduced to ash by proximity. Or cooked inside them.

I can't recall the thread this was brought up in, but wasn't that very speculation brought up regarding droidekka shields? Something about how personal shields were much less hardy than the Clone war era.

[Surlethe]

Observation: device maintains constant altitude.
Deduction: device is doing no work.
Conclusion: device is not expending energy.

That's a pretty shaky conclusion, since you don't need to do work in order to expend energy. Just look at such beasts as hovering helicopters (which are actually doing work on the air, but not the gravitational field; but in any case, the engines are expending much more energy than the work they're doing). The official literature says that repulsorlifts don't need energy to maintain a constant altitude, but given we have no way of knowing how such a device would work, it's not a conclusion you can make out of hand based only on the observation that it doesn't do any work against the gravitational force.

The wording is oversimplified. What it should say is "Conclusion: device does not necessarily need to expend energy".

I stand corrected. Thank you.

[Cykeisme]

Perhaps the effectiveness of personal shields relates to how it reacts to incoming weapon fire, not just whether you can switch it on.

Capital ships radiate heat from incoming weapons fire as neutrinos, right?

It seems highly likely that the neutrino radiation technology simply doesn't scale down. Hence, personal shielding is going to simply have to re-radiate incoming heat over time. Whether it's trapped within the shield bubble or radiated off the shield "surface", it's hard to say.

Thus, if's possible that you may be able to switch on a personal shield, but it's not very helpful if you get cooked (albeit more evenly, yum!) after the shield gets hit

It's possible that droidekas become pretty damn hot in there!

[Marko Dash]

how effective of an anti personal weapon would it be (against non-sealed troops) if the droidekas let that heat and pressure build for awhile and then pulsed the shields? wouldn't we hear a distinct sound when the shields dropped if they worked like this.

[Batman]

how effective of an anti personal weapon would it be (against non-sealed troops) if the droidekas let that heat and pressure build for awhile and then pulsed the shields? wouldn't we hear a distinct sound when the shields dropped if they worked like this.

I rather suspect that even given Wars infantry weapons for this tactic to work (even if the Droideka's can withstand the heat and pressure for long enough) that would require them to stay shielded, under continuous fire, for DAYS at the very least. Chances are they'd be much better off simply shooting back.

[Connor MacLeod]

The excecuse given for Droideka shields is radiation. Whether its from the generator itself (some exotic technobabble radiation, or perhaps secondary radiation from shield/atmosphere interactions of the visible effect, we dont know.)

There could be some problems with internal heating of a shield's interior (from the aformentioned shield interaction - this depends on how much, if any, energy the shields expend. As noted, shields need not expend any energy.)

another probable limitation is that any sort of deflector is going to be highly detectable even if it is safe, so this limits your stealth options.

Alot of sources say that personal shields need some sort of larrge power supply to be sustained, but exactly how much energy is not known. It could be this refers not to just only the generator, but the associated cooling systems (for the pwoer source and the generator) being too bulky. Most viable "shields" tend to be fairly localized (protecting a part of the body) and incorporated into some larger bit of armour (or backpack mounted - Kyle Katarn's is an example of the former and the latter was featured in the Black Fleet crisis.) What a shield would need to use energy for is anyone's guess, but I suppose it depends on the kind of shield. Some "matter" based shield may need energy, or particle shields, but personal particle shielding is both rare and unneeded (msot body armour is impervious to projectiles, ie Stormie armour.)

Most "practical" applications of personal shields seem to be limited either to some sort of energy absorption/heat sink system built into a solid armour system (stormtrooper armour and clonetrooper armour are an example of this) or some sort of physical "Shield" (The Gungan shields being an example of this, but other barriers.) In most other caes you just see man-portable but essentially static barriers.

[wjs7744]

Good grief, are people still arguing about power levels for shields, I thought Mike covered that well enough on the main site.

Maybe I can add a little more.
We don't have anything precisely analogous to an energy shield, but consider the refrigerator. It's job is to dump heat (energy) out of the system. Now, what happens if you ramp up the input power by an order of magnitude; will it start cooling things down at ten times the rate, or will it just melt? I'll leave you to answer that.

[Wanderer]

Manual loaded turbolasers? Shells = batteries?

Those are the flak guns I believe. They do require shells.

Its a combination Ion Cannon/mass driver weapons mount.according to ROTS Visual Dictionary on Page 4. The Ion Cannon is above the mass driver part and is firing red beams continuously if you watch closely the scene in question.