|
|
|
Dave W.
Info Junkie
USA
26022 Posts |
 Posted - 08/10/2005 : 17:05:27 [Permalink]
|
quote:
Originally posted by me
...solve for d in the equation c=d2/(1-d)2?
Wait! Nevermind...
0 = d2 - d/2 - (c-1)
And then I'll quadratic formula the sucker in a few minutes... |
- Dave W. (Private Msg, EMail)
Evidently, I rock!
Why not question something for a change?
Visit Dave's Psoriasis Info, too. |
 |
|
|
pleco
SFN Addict
USA
2998 Posts |
Posted - 08/10/2005 : 17:09:41 [Permalink]
|
| And I thought trigonometry, algebra, and calculus would have no useful purpose outside of college! |
by Filthy
The neo-con methane machine will soon be running at full fart. |
|
|
|
|
ktesibios
SFN Regular
USA
505 Posts |
Posted - 08/10/2005 : 17:12:44 [Permalink]
|
quote:
Originally posted by Dave W.
Any math geeks want to help me solve for d in the equation c=d2/(1-d)2? I seem to have forgotten how to do so. Of course, 10th grade was so very long ago...
I'll try. This is what I get:
c=d2/(1-d)2
sqrt(c)= d/(1-d)
That's the same as a=x/(b-x), where a= sqrt(c), b=1 and x=d. So, to make this all easier to type, I work it:
a=x/(b-x)
a/x=1/(b-x)
x/a=b-x
(x/a)+x=b
x+ax=ab
x(1+a)=ab
x=ab/(1+a)
Plugging in the equivalents for a, b and x, I get
d=sqrt(c)/(1+sqrt(c))
This is very similar to a voltage divider problem I've had to solve umpteen times, except that the sign of x is opposite. Hope I got it right.
 |
"The Republican agenda is to turn the United States into a third-world shithole." -P.Z.Myers |
|
|
|
Dry_vby
Skeptic Friend
Australia
249 Posts |
Posted - 08/10/2005 : 17:57:58 [Permalink]
|
OK< here's my go:
c=dsq/(1-d)sq
cdsq - 2cd + c =dsq
(C-1)dsq - 2cd+c=0
d = 2c +/- sqrt 4csq-4c(c-1)
over 2(c-1)
2(c +/- sqrt4c)
over2(c-1)
2(c +/- sqrtc)
over2(c-1)
Provided the value of c is not less than 0. Then it becomes complex. |
"I'll go along with the charade
Until I can think my way out.
I know it was all a big joke
Whatever it was about."
Bob Dylan
|
|
|
|
Dave W.
Info Junkie
USA
26022 Posts |
Posted - 08/10/2005 : 18:23:07 [Permalink]
|
quote:
Originally posted by ktesibios
I'll try. This is what I get:
c=d2/(1-d)2
sqrt(c)= d/(1-d)
Argh! In the car on my commute home, I had myself convinced that the sqrt of a2/b2 was not a/b. I blame the traffic.quote:
d=sqrt(c)/(1+sqrt(c))
Okay, for c plug in the ratio of the Sun's mass to Saturn's mass, and we find the equi-gravity point between the two is 98.33% of the way to Saturn, so Saturn's gravity becomes the stronger of the two forces only 24 million km (or so) from Saturn. The Sun dominates interplanetary travel.
...And now, plugging in the numbers supplied by sts60, I find that my Cassini is slowing down by only half as much as the real thing, so something is wrong with my model... |
- Dave W. (Private Msg, EMail)
Evidently, I rock!
Why not question something for a change?
Visit Dave's Psoriasis Info, too. |
|
|
|
woolytoad
Skeptic Friend
313 Posts |
Posted - 08/10/2005 : 19:08:36 [Permalink]
|
Why is it c = d^2/(1-d)^2?
If c is the ratio of masses M1 and M2 (Sun and Saturn, whatever), shouldn't we be solving c=d^2/(D-d)^2 where D is the distance between the M1 and M2?
Since gravitational force on a body F=GMm/r^2
Assume large masses M1 and M2 are stationary. Distance to 3rd body (probe) is r and d respectively. We equate forces.
So
M1/r^2 = M2/d^2
but d = D-r
M1/M2 = r^2/(D-r)^2
Are we dividing by D for some reason?
Are the orbits elliptical enough for the variation in distance to matter? |
|
|
|
Dave W.
Info Junkie
USA
26022 Posts |
Posted - 08/10/2005 : 19:19:33 [Permalink]
|
quote:
Originally posted by woolytoad
Are we dividing by D for some reason?
Yes, so we get the ratio to big-D (effectively a percentage), first, since it is what I was more interested in. Little-d, for two given masses, is the same no matter what big-D is. We can then multiply little-d by big-D to get the actual distance to the L1 point.
d = sqrt(m1/m2)/(1+sqrt(m1/m2)) |
- Dave W. (Private Msg, EMail)
Evidently, I rock!
Why not question something for a change?
Visit Dave's Psoriasis Info, too. |
|
|
|
Cuneiformist
The Imperfectionist
USA
4955 Posts |
Posted - 08/10/2005 : 20:13:21 [Permalink]
|
quote:
Originally posted by bigbrain
sts60 wrote:
"... It's really quite simple. You claimed NASA engineers don't take Earth's velocity into account. I provided explicit examples of NASA (and contractor) engineers taking Earth's velocity into account in mission planning, in particular for the Cassini mission ..."
It's not quite simple.
NASA engineers don't take Earth's velocity into account.
NASA engineers are only buffoons who write, write and write but do only craps, craps and craps. 
I'm confused. Either NASA people did take this into account, or thay didn't. And since sts60 makes sense, and since he doesn't use lots of similey-faces in hist posts-- ans since he's not a jack-ass, I'm wagering he's right. So WTF? Did we or didn't we? |
|
|
|
Starman
SFN Regular
Sweden
1613 Posts |
Posted - 08/11/2005 : 01:26:59 [Permalink]
|
So the NASA is being debunked by an individual that has no grasp of basic mechanics.
Slightly amusing, but mostly painful...
I |
|
|
|
filthy
SFN Die Hard
USA
14408 Posts |
Posted - 08/11/2005 : 02:31:49 [Permalink]
|
quote:
Originally posted by Cuneiformist
quote:
Originally posted by bigbrain
sts60 wrote:
"... It's really quite simple. You claimed NASA engineers don't take Earth's velocity into account. I provided explicit examples of NASA (and contractor) engineers taking Earth's velocity into account in mission planning, in particular for the Cassini mission ..."
It's not quite simple.
NASA engineers don't take Earth's velocity into account.
NASA engineers are only buffoons who write, write and write but do only craps, craps and craps.
I'm confused. Either NASA people did take this into account, or thay didn't. And since sts60 makes sense, and since he doesn't use lots of similey-faces in hist posts-- ans since he's not a jack-ass, I'm wagering he's right. So WTF? Did we or didn't we?
Ummm, yes.... I rather think that the only velocity NASA engineers failed to figure for is that of the spin bb and other conspiracy hobbiests put upon what they do.
As I am not scientificly literate in this field, I must approach it from a different direction: "Follow the money!"
If it's all a big, fat swindle as alledged by bb, how come there are so many working stiffs at NASA? I mean, we're talking, not paltry millions, but nice, plump billions and lots of them, all embezzled from the taxpayer (and poaching in the polititian's private forest). Where are the yatchs(sp?)? Where are the retired, jet-setting engineers, flitting about the European casinos in tuxedos, eating snails and goose liver, and swilling wines with names that no one can pronounce?
Further, who is running the rip-off department at NASA? We can ID highly secretive drug lords in Colunbia, but we can't find and bust the domestic kingpin of a long-running, multi-hundred billion dollar conspiracy? Gimmie a break; not even the FBI is that stupid! Or indeed, corrupt, for this would certainly have to involve bought-off law enforcement on a grand scale.
And where are the snitches; or, perhaps more to the point, where are their corpses? How come no floating, NASA stoolies have frightened the naked beach-apes, washing in with the flood tide?
sts60 is correct for more reasons that the ones he has stated. Until bb can come up with a little more than hand-waving and blather, his conjecture must be dismissed.
Edit: I have read that some private company will, in the not-too-distant future, be offering vacation trips around the moon for 100 grand per (I lost the link, sorry). Will this too, be a hoax, assuming that it gets off the ground?
 |
"What luck for rulers that men do not think." -- Adolf Hitler (1889 - 1945)
"If only we could impeach on the basis of criminal stupidity, 90% of the Rethuglicans and half of the Democrats would be thrown out of office." ~~ P.Z. Myres
"The default position of human nature is to punch the other guy in the face and take his stuff." ~~ Dude
Brother Boot Knife of Warm Humanitarianism,
and Crypto-Communist! 
|
| Edited by - filthy on 08/11/2005 02:39:21 |
|
|
|
bigbrain
BANNED
409 Posts |
Posted - 08/11/2005 : 02:57:57 [Permalink]
|
quote:
Originally posted by Starman
So the NASA is being debunked by an individual that has no grasp of basic mechanics.
Slightly amusing, but mostly painful...
I
Hey, don't say craps. I'm from the same country of Leonardo da Vinci, the father of airplane, helicopter and mechanical machines.
SECOND STATEMENT: NASA's buffoons say the probe passes near Venus and Venus increases its velocity. COMPLETELY FALSE.
Venus is not magic, it has no capacity to increase spacecraft's velocity.
Venus hasn't hands to give a push to the probe.
|
"Obsequium amicos, veritas odium parit" (Flattery gets friends, truth hatred)
Publius Terentius Afer, "Terence", Roman dramatist
|
|
|
|
filthy
SFN Die Hard
USA
14408 Posts |
Posted - 08/11/2005 : 04:00:16 [Permalink]
|
quote:
Originally posted by bigbrain
quote:
Originally posted by Starman
So the NASA is being debunked by an individual that has no grasp of basic mechanics.
Slightly amusing, but mostly painful...
I
Hey, don't say craps. I'm from the same country of Leonardo da Vinci, the father of airplane, helicopter and mechanical machines.
SECOND STATEMENT: NASA's buffoons say the probe passes near Venus and Venus increases its velocity. COMPLETELY FALSE.
Venus is not magic, it has no capacity to increase spacecraft's velocity.
Venus hasn't hands to give a push to the probe.
But Venus does indeed have hands to push the probe. They're called 'Gravity.' Even an ignoramous such as myself knows that, and you are in no position to call anyone a buffoon.
Now then, where's the money? How was it laundered and who ended up with how much?
On edit: I fail to see what the bolded statement has to do with the discussion at hand. Leonardo was truly one of the great thinkers of any age, but I am reminded that his homeland also gave us such miscreants as Pope Innocent III (nee- Lotario d'Conti), Il Duce, the Borgia family, and Salvatore 'Lucky' Luciano.
What pray, is your point?
|
"What luck for rulers that men do not think." -- Adolf Hitler (1889 - 1945)
"If only we could impeach on the basis of criminal stupidity, 90% of the Rethuglicans and half of the Democrats would be thrown out of office." ~~ P.Z. Myres
"The default position of human nature is to punch the other guy in the face and take his stuff." ~~ Dude
Brother Boot Knife of Warm Humanitarianism,
and Crypto-Communist!
|
| Edited by - filthy on 08/11/2005 05:19:22 |
|
|
|
BigPapaSmurf
SFN Die Hard
3192 Posts |
Posted - 08/11/2005 : 05:49:02 [Permalink]
|
Hes just pointing out that Italian birth usurps all educatioan and those born there are infused with the spirit of LDV and therefor are unstopable logic robots.
Oh you forgot Caligula and Nero (assuming they were home grown) |
"...things I have neither seen nor experienced nor heard tell of from anybody else; things, what is more, that do not in fact exist and could not ever exist at all. So my readers must not believe a word I say." -Lucian on his book True History
"...They accept such things on faith alone, without any evidence. So if a fraudulent and cunning person who knows how to take advantage of a situation comes among them, he can make himself rich in a short time." -Lucian critical of early Christians c.166 AD From his book, De Morte Peregrini |
|
|
|
sts60
Skeptic Friend
141 Posts |
Posted - 08/11/2005 : 06:19:08 [Permalink]
|
NASA has just scrubbed the launch of Mars Reconaissance Orbiter today (August 11).
A crestfallen NASA official sheepishly admitted, "We forgot to take Earth's velocity into account." |
|
|
|
Valiant Dancer
Forum Goalie
USA
4826 Posts |
Posted - 08/11/2005 : 06:27:27 [Permalink]
|
quote:
Originally posted by bigbrain
Dear friend sts60
What can 3 kilograms cause to a probe going at 59,250 or 80,000 or 101,000 miles per hour?
Depends on the speed that the 3kg item is traveling. It could slam into your probe and do some serious damage.
Please remember that kilograms are units of mass and force is mass times acceleration (essentially speed of the mass). This is usually expressed as F=MA. |
Cthulhu/Asmodeus when you're tired of voting for the lesser of two evils
Brother Cutlass of Reasoned Discussion |
|
|
 |
|
|
|
Topic Locked
