physics vs. ST

[mudmunkey]

Speaking in terms of physics, impulse = (F) Delta t, or force multiplyed by change in time. How does this kind of impulse relate to the impulse drive, and if it doesnt, why does it have the same name?
I have spaced off in my physics class every time impulse is mentioned over this, and need some answers before i go insane!

[Dalton]

Moved to SLM.

[data_link]

It has no relation whatsoever to "impulse" drive. The reason for using the same name is because the Trek writers' motus operandi is to take a RW technical term, assign a completely arbitrary meaning to it, and then string them together in a random fashion in order to create that all-purpose resource for solving any problem: treknobabble!

Oh, by the way, since you are a n00b, you are entitled to a free complimentary POKE on behalf of the citizens of SD.net.

POKE!

Enjoy your stay.

[Darth Wong]

Impulse is a Newtonian physics term. It relates to change in momentum.

[Durandal]

If you want an idea of what impulse is, look at the equation.

I = F(Delta-t)

Since

F = ma,

you can substitute that expression into the equation for impulse to get

I = ma(Delta-t).

You can also see that

Delta-t = t_f - t_i.

Substituting that in, the equation becomes

I = ma(t_f - t_i).

Expanding it out, we get

I = ma(t_f) - ma(t_i).

Replacing each with their units, you see

I = (kg)(m/(s^2))(s) - (kg)(m/(s^2))(s),

which goes to

I = (kg)(m/s) - (kg)(m/s).

So, impulse can be rewritten as

I = mv_f - mv_i,

Since

p = mv,

we get

I = p_f - p_i.

In other words, the difference between the final momentum and the initial momentum, or the change in momentum, as Mike said, is the impulse. Hope this helps.

[mudmunkey]

I get the idea of impulse, I just didnt know if there was a relation between ST's "impulse" engines and the actual thing. I used about the same way to get the relation, only I like mine better

Impulse= force*time
force= mass*acceleration
acceleration=(delta velocity/ time)
force= mass*(delta velocity/time)
impulse=mass*delta velocity/time*time
impulse=mass*delta velocity=delta momentum
impulse=delta momentum

yay! this is the THIRD time Ive typed this and then had trouble posting, so if this doesn't get through.....you won't be reading it right now.

[Darth Wong]

I get the idea of impulse, I just didnt know if there was a relation between ST's "impulse" engines and the actual thing.

There would be, except that those little engines can't possibly generate enough impulse to push the ship, so out comes the "subspace" cop-out ...

[data_link]

And then there is the fact that Trek writers apparently don't understand the concept of "inertia," so out comes the speed limits and the banking turns...

[ClaysGhost]

And then there is the fact that Trek writers apparently don't understand the concept of "inertia," so out comes the speed limits and the banking turns...

Yes, in common with almost every other sci-fi show and film. Actually, I wonder if we can come up with a list of shows that don't do this?

[The Dark]

And then there is the fact that Trek writers apparently don't understand the concept of "inertia," so out comes the speed limits and the banking turns...

Yes, in common with almost every other sci-fi show and film. Actually, I wonder if we can come up with a list of shows that don't do this?

Speed limits make sense only so far as what the radiation and/or particle shielding can handle. Really, it would all be acceleration (as we all know, but reinforcement is a good thing). I hate to point this out, but we see some banking turns in SW also.

[ClaysGhost]

Speed limits make sense only so far as what the radiation and/or particle shielding can handle. Really, it would all be acceleration (as we all know, but reinforcement is a good thing). I hate to point this out, but we see some banking turns in SW also.

We also see non-accelerating ships with their engines lit as well (ST and SW).

[Durandal]

Let' not forget the scene in ST3 where conservation of momentum was tossed out of a ten-story building and then had a piano dropped on it.

[kheegster]

Technically, any type of engine that moves a vehicle can be called an impulse drive, I think...if it provides impulse to move the vehicle...

KG

[data_link]

Technically, any type of engine that moves a vehicle can be called an impulse drive, I think...if it provides impulse to move the vehicle...

KG

Given how quickly the Enterprise reaches maximum speed however, it would make more sense to call it a "thrust" drive.

[The Dark]

Let' not forget the scene in ST3 where conservation of momentum was tossed out of a ten-story building and then had a piano dropped on it.

Is that the Kirk falling off a mountain scene? That one definitely bugs me.

[Warspite]

Let' not forget the scene in ST3 where conservation of momentum was tossed out of a ten-story building and then had a piano dropped on it.

Is that the Kirk falling off a mountain scene? That one definitely bugs me.

I think he's talking about Kirk firing a phaser and the Klingon doing a Superman impression.

[The Dark]

Let' not forget the scene in ST3 where conservation of momentum was tossed out of a ten-story building and then had a piano dropped on it.

Is that the Kirk falling off a mountain scene? That one definitely bugs me.

I think he's talking about Kirk firing a phaser and the Klingon doing a Superman impression.

Oh, true, Kirk falling off the mountain was in ST5. That always bugged me, because Kirk should have still been injured from the suddenness of the stop (Spock didn't curve the catch to turn vertical motion in a horizontal direction).

[Durandal]

No, I was talking about the scene where the Excelsior's engines go offline and it coasts to a stop.

[Kosh_The_Vorlon]

And then there is the fact that Trek writers apparently don't understand the concept of "inertia," so out comes the speed limits and the banking turns...

Yes, in common with almost every other sci-fi show and film. Actually, I wonder if we can come up with a list of shows that don't do this?

You'd have, AFAIK, Babylon 5 and maybe Stargate (I haven't seen enough space scenes to make a judgement call on that one)

[kojikun]

Newtonian physics scifi would be first season andromeda (they had a kilometer long ship flip upside down and reverse direction in less then 5 seconds.. ) , B5, and maybe SG but they so rarely have anything smaller then a transport shown. I think they OCCASIONALLY have ships fly circles around larger ones, but i cant be sure.

[ClaysGhost]

And then there is the fact that Trek writers apparently don't understand the concept of "inertia," so out comes the speed limits and the banking turns...

Yes, in common with almost every other sci-fi show and film. Actually, I wonder if we can come up with a list of shows that don't do this?

You'd have, AFAIK, Babylon 5 and maybe Stargate (I haven't seen enough space scenes to make a judgement call on that one)

B5 appears reasonably good as regards the lack of banking turns (and I don't remember that many SG space scenes). Both have other physics problems, but probably not this one.

[Lord Edam]

No, I was talking about the scene where the Excelsior's engines go offline and it coasts to a stop.

If it was using AMRE at the time then conservation of momentum would tie in nicely with the extended physics of mass lightening and a gradually decaying AMRE field.

There is no contradiction of the laws of physics here. Only an extension to them.

[Captain Hornblower]

As I recall, the "Trans-Warp Drive" had not been engaged, so, would the mass lightening effects have taken effect yet? Also, isnt the matter-antimatter reactor just that, a means of controlling matter-antimatter reactions and suppling power to the ship, whereas the warp-drive is the actuall mechanism that provides the mass-lightening effects and propels the ship at super-luminal velocities.

[InnerBrat]

All this is why I hate it when people call ST Science Fiction.
Science my arse. It's a space opera.

[Warspite]

No, I was talking about the scene where the Excelsior's engines go offline and it coasts to a stop.

Oh, THAT scene! Right, well, I tend to disregard that whole episode, after all, the Excelsior behaves like a truck with a banana on it's tail pipe!
Could it be that the mass-lightening effect disapears completely, and the ship get's it's full mass back on real-space? Well, Scotty could arrange for that, couldn't he?