Momentum and Shield Generators - help needed

[Chardok]

I've always thought that shields absorbing kinetic impactors should act as a sort of shock absorber, but still allow the shield to "Shift" in the direction of the impact (towards the hull) all the while distributing the force of the impact over a wide area before it finally contacts the hull. Thus saving the generator from destruction and the ship as well....did that make sense?

[Ted C]

The person I'm arguing against says that its wrong according to physics for a shield generator to have an effect on something outside the hull without also having an effect on the rest of the ship, as he says it, field effects are 'line-of-sight'. Because of this, he says, the bit of hull directly between the projextile and the shiels generator is actually the part of the ship that as taking the momentum, and from there, it spreads to the rest of the ship. He says that momentum cant be transferred without direct contact, for some reason. He also says that there must be shield emitters on the hull because of the beforementioned problem.

I wonder if anyone else has pointed out that field effects are not line of sight. Put a strong magnet inside an opaque cardboard box and its magnetic field will still exert force outside the box. Also, if you know where in the box the north end of the magnet lies, you can approach it with the north end of another magnet from the outside, and the repelling force will be exerted against the interior magnet, not the cardboard that lies between the magnets.

[Darth Wong]

I've always thought that shields absorbing kinetic impactors should act as a sort of shock absorber, but still allow the shield to "Shift" in the direction of the impact (towards the hull) all the while distributing the force of the impact over a wide area before it finally contacts the hull. Thus saving the generator from destruction and the ship as well....did that make sense?

That would make sense if the shield is a physical cushion rather than a forcefield, and if it had some "give" in it.

[Darth Servo]

The person I'm arguing against says that its wrong according to physics for a shield generator to have an effect on something outside the hull without also having an effect on the rest of the ship, as he says it, field effects are 'line-of-sight'. Because of this, he says, the bit of hull directly between the projextile and the shiels generator is actually the part of the ship that as taking the momentum, and from there, it spreads to the rest of the ship. He says that momentum cant be transferred without direct contact, for some reason. He also says that there must be shield emitters on the hull because of the beforementioned problem.
Good rebuttals against his argument would also be good.

How about pointing out that he's making things up out of thin air. Sci-fi shields are a completely fictional piece of technology. Why is it these buffoons think they get to make up ideas out of thin air for how they work?

I can't think of any sci-fi series where they state that their shields are limited to line of sight the way this guy insists. EM is largely limited by line of sight. Anyone who has experienced an earthquake knows this does not hold true for all phenomena in the universe.

[Darth Wong]

You don't need to know how shields work in order to refute his idiotic general statements that field effects require a line of sight.

[Winston Blake]

I don't think it's as simple as that. The firing and defending ships both feel the same impulse, not force.

Forces and torques are just the first time derivatives of linear and angular momentum, therefore in a conservative system they must sum to zero.

The forces do sum to zero, at any given point in time. However, that doesn't mean the force on each ship must be equal. Throughout the 'pitching' event, the projectile and ship feel equal and opposite forces. In transit, none of the bodies feel any force. Then throughout the 'catching' event, the projectile and other ship feel equal and opposite forces again. But these may be of different magnitude to those in the pitching part, depending on the duration of each event.

I wonder if anyone else has pointed out that field effects are not line of sight. Put a strong magnet inside an opaque cardboard box and its magnetic field will still exert force outside the box. Also, if you know where in the box the north end of the magnet lies, you can approach it with the north end of another magnet from the outside, and the repelling force will be exerted against the interior magnet, not the cardboard that lies between the magnets.

Sure, but put the magnet inside a metal box and the situation changes. Or put a charge between two charges, or a mass between two masses. I'm guessing the idea is that since a shield can affect impactors with the same nature as the ship's structure, the ship should be affected.

Still, this baselessly assumes that the shield force must monotonically increase as you get closer to the emitter. In fact, by his logic, the shield emitters cannot possibly be covered or armoured; they must be completely exposed to space, and therefore visible. If he can't point out where the exposed shield emitters are on a picture of any ship, then they must at least be covered by a panel. If this panel lies within a dead zone, then why shouldn't much of the ship lie in such a region, making the emitter internal?

This guy didn't "clarify" his argument; he's simply weaseling around trying to save it. I'm sure he initially believed that it is simply impossible to project force through obstacles, completely forgetting the examples of gravity and electromagnetism.

He's still arguing that. His point of contention is that this isn't the case in ST, because we saw a case where the ship rolled with the impact from weapons fire.

It isn't wrong, but that doesn't make what hig saying wrong either. There simply isn't a "jump" through matter.

I don't understand. What does he think rolling proves?

[Darth Servo]

I didn't think I was saying we needed to know how shields work. I thought I was pointing out that the idiot in question here clearly thinks HE knows how they work and arbitrarily making up rules for them to follow.

[Paolo]

The forces do sum to zero, at any given point in time. However, that doesn't mean the force on each ship must be equal. Throughout the 'pitching' event, the projectile and ship feel equal and opposite forces. In transit, none of the bodies feel any force. Then throughout the 'catching' event, the projectile and other ship feel equal and opposite forces again. But these may be of different magnitude to those in the pitching part, depending on the duration of each event.

I'm agreeing with you precisely on that point. It follows straightforwardly starting with the conservation laws.

p_a1 + p_p1 + p_d1 = p_a2 + p_p2 + p_d2 = p_tot = C
dp_a1 = -dp_p1
dp_p2 = -dp_d2

dp1/dt_1 + dp2/dt_2
= dp_a1/dt_1 + dp_p1/dt_1 + dp_p2/dt_2 + dp_d2/dt_2
= 0/dt_1 + 0/dt_2
= 0
= dp_tot/dt_1 = dp_tot/dt_2

As you can see, dt_1 and dt_2 are free to vary as you please. An obvious example is forensics ballistics, provided the water tank has enough give to stop the bullet before it hits the wall.

[Winston Blake]

I'm agreeing with you precisely on that point.

Oh, I thought you were refuting the bit you quoted. Sorry.