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Cute Wolf
08-01-2011, 11:13
the rules is rather simple:
- ask a question about science principles/applications (maths, physics, chemistry, biology, astronomy, geology, etc), but NOT social sciences (economy, politics, socials, etc - since they're pretty subjective).
- you can obviously search and use everything to give the correct answer, and the reasonings behind, or cite a source.
- the one with correct answer can ask another question, till someone answer correctly.


well, I'll start with a rather easy one first:

why accidental methanol (wood alcohol - which was poisonous) poisonings could be easily treated by giving alcoholic drinks to the patient?

Major Robert Dump
08-01-2011, 12:34
BECAUSE THE BEST CURE FOR A HANGOVER IS TO DRINK MORE.

WIN.

Cute Wolf
08-01-2011, 13:01
BECAUSE THE BEST CURE FOR A HANGOVER IS TO DRINK MORE.

WIN.

wrong :clown:

well, it's the very simplified outer effects :grin: , but then, the hint is, the process involve "some ways" of human metabolic system.

Skullheadhq
08-01-2011, 13:17
wrong :clown:

well, it's the very simplified outer effects :grin: , but then, the hint is, the process involve "some ways" of human metabolic system.

it's human simple alcohol metabolism :
- the ethanol is metabolized in our body via enzymatic catabolic metabolism, which was reactive to the hydroximethyl functional group
- methanol has the same hydroximethyl functional group -CH2-OH , identical with those present in ethanol
methanol:
https://upload.wikimedia.org/wikipedia/commons/thumb/f/f1/Methanol_Lewis.svg/121px-Methanol_Lewis.svg.png
ethanol:
https://upload.wikimedia.org/wikipedia/commons/thumb/e/e8/Ethanol-structure.svg/121px-Ethanol-structure.svg.png

- in human metabolism, both methanol and ethanol undergo oxidation process, the hydroximethyl group will be converted to carboxilic acid group -CH2-OH --(o)--> -COOH
- ethanol is not so poisonous since the metabolic result is acetic acid (vinegar), but methanol is poisonous because the metabolic result is the formic acid, a strong oxidator that can damage internal organs.

if we view the other side of molecular structure, ethanol has CF3- while methanol only has H- ; that means ethanol is better binding agent on catabolic enzymes. In presence of both ethanol and methanol molecules, they undergo competitive inhibition process, and since ethanol will be better bind with the enzyme, and in case of accidental poisonings, ethanol will be flushed in greater concentration than methanol, the enzymatic equilibrum will fall far toward ethanol metabolism rather than methanol metabolism. The net effect is, only a few fraction of formic acid formed, and a lot of acetic acid formed, plus, the formed formic acid from methanol will self-oxidize the resident ethanol, so they're neutralized to CO2 and H2O in the end, without damaging internal organs.

dammit, you make me open my hated chemistry book!

Cute Wolf
08-01-2011, 13:18
that's right, you may ask the next scientific question :D

Skullheadhq
08-01-2011, 13:22
that's right, you may ask the next scientific question :D

why two coils placed close, but no contact with each others will transfer their electric currents to each others, assuming closed circuit system? despite they technically make no direct contact?

rajpoot
08-01-2011, 13:37
why two coils placed close, but no contact with each others will transfer their electric currents to each others, assuming closed circuit system? despite they technically make no direct contact?

off the top of my head, depending on the voltage applied the air between the coils will get ionised allowing current to pass.

TinCow
08-01-2011, 14:54
- ask a question about science principles/applications (maths, physics, chemistry, biology, astronomy, geology, etc), but NOT social sciences (economy, politics, socials, etc - since they're pretty subjective).

Bah, there are as many correct answers in the social sciences are there are in the hard sciences.

drone
08-01-2011, 15:47
why two coils placed close, but no contact with each others will transfer their electric currents to each others, assuming closed circuit system? despite they technically make no direct contact?

Alternating or direct current?

xploring
08-01-2011, 15:57
Something about Magnetic field <-> Electric field inducting each other, or something... I used to be smart, not any more... -_-

Skullheadhq
08-01-2011, 17:27
Oh lawd, never knew I was this good in chemistry, but I am.

Kralizec
08-01-2011, 17:38
why two coils placed close, but no contact with each others will transfer their electric currents to each others, assuming closed circuit system? despite they technically make no direct contact?

On the top of my head: the first coil emanates an electromagnetic field, wich creates electric currents in the second coil. Having coils of different sizes causes the voltage to differ; i.e. a transformer.

Tellos Athenaios
08-01-2011, 17:42
In the simplest terms air is only dielectric (non conductive) because its intrinsic resistance (probably the wrong term, soortelijke weerstand, what is for electric resistance in ohm what density is for mass in kg) is so high. However the resistance increases (or decreases) linearly with the distance in the medium which must be crossed, as a result if the gap is small enough your resistance nears to small enough that the potential on the circuit is large enough for current to pass through this resistance.

Additionally, the circuit generates an electric field (on all parts of the circuit, that is what happens when electric charge is shifted and also why CAT cables often employ a twisted pair design to negate the effects of the electric field on signal reception at the other side) which may be sufficiently strong to generate “static electricity” as the coils become “charged”.

Depending on the potential on the circuit and distance between the coils either one is the likely explanation. (At relatively low voltages/large gaps the coils act as a capacitor and the electric field explanation applies, or at very small distances or high voltages the air is not sufficiently resistant to block the electric current.)

EDIT: I am assuming the circuit looks like this in my poor ASCII art representation:



---| :---
| |
|--C C--|


| : is the source of potential (i.e. a wall socket), the - and | are bits of wiring, and the C's are coils.

Tellos Athenaios
08-01-2011, 17:52
On the top of my head: the first coil emanates an electromagnetic field, wich creates electric currents in the second coil. Having coils of different sizes causes the voltage to differ; i.e. a transformer.

No, transformers work without electric current passing through the air, and crucially only work properly on an AC circuit because they rely on induction as a result of [i]change in magnetic field. (Namely: alternating direction of magnetic field, the differences in field strength is what determines the difference in output potential and current [ignore the effects of resistance in the coil system] and the field strength is determined by more than just size).

Kralizec
08-01-2011, 18:05
*brains explode*

Skullheadhq
08-01-2011, 18:06
In the simplest terms air is only dielectric (non conductive) because its intrinsic resistance (probably the wrong term, soortelijke weerstand, what is for electric resistance in ohm what density is for mass in kg) is so high. However the distance increases (or decreases) linearly with the distance in the medium which must be crossed, as a result if the gap is small enough your distance nears to small enough that the potential on the circuit is large enough for current to pass through this resistance.

Additionally, the circuit generates an electric field (on all parts of the circuit, that is what happens when electric charge is shifted and also why CAT cables often employ a twisted pair design to negate the effects of the electric field on signal reception at the other side) which may be sufficiently strong to generate “static electricity” as the coils become “charged”.

Depending on the potential on the circuit and distance between the coils either one is the likely explanation. (At relatively low voltages/large gaps the coils act as a capacitor and the electric field explanation applies, or at very small distances or high voltages the air is not sufficiently resistant to block the electric current.)

EDIT: I am assuming the circuit looks like this in my poor ASCII art representation:



---| :---
| |
|--C C--|


| : is the source of potential (i.e. a wall socket), the - and | are bits of wiring, and the C's are coils.

correct :bow:
now, you're next :creep:

Tellos Athenaios
08-01-2011, 20:35
This one is looking for an algorithm that could conceivably be used to plot a bisector on a screen.
Below some rules for answers to make sure we can understand what we come up with:

Suppose you a have a 2d coordinate system. Points are defined through the function point which takes an x and y coordinate and returns a point. Then there is a function y which takes a point and returns its y coordinate, likewise there is a function x which take as a point an returns its x coordinate. There is a function d() to compute distance between two points and a function sqrt() to compute the square root of real number. (E.g.: d(K,L) is 5 if the distance between points K and L is 5.) You can use the following comparison operators, where a and b are variables used for explaining how they work:


-- test if a is less than or equal to b
a <= b
-- test if a is greater than or equal to b
a >= b
-- test if a is equal to b
a == b
-- test if a is not equal to b
a != b
-- test if a is less than b
a < b
-- test is a is greater than b
a > b

These operators will also work to compare variables with values, e.g. you could write something like a == 0 to test if variable a is 0.
You also get two boolean operators to combine multiple comparisons && for logical and, and || for logical (inclusive) or.

Additionally, you can use the following arithmetic operators: × (multiplication of two real numbers), ÷ (division of two real numbers), + (sum of two real numbers), - (subtracts one real number from another real number).

You are able to define branches in your algorithm using if-else syntax, where if takes an expression which must evaluate to a boolean (true or false). E.g. to test if a variable div is 0:


if div == 0
-- proceed with one branch
else
-- proceed with another.


The operator precedence (the mechanism which determines how an expression like 5 - 3 * 4 is evaluated) for the defined operators is (from highest to lowest):

×, ÷ (they have equal precedence values)
+, -
&&, ||
== , != , <=, >=, >, <
, (the comma operator)


You can use parentheses to group expressions. Thus: ((5-3) * 4) != (5 - 3 * 4) returns true.

Finally you are able to define new variables using <name> = <value> notation. E.g. to define a variable z as the distance between two points P and Q you would write:


z = d(P,Q)


Names must not be numeric constants the names of operators, existing functions or existing variables. Note that this means you are not able to redefine variables, so the following will NOT work:


z = d(P,Q)
z = z + 1 -- this will not work, because z already exists and is defined to d(P,Q).


You can define functions using shortened form of lambda notation (where \ denotes the lambda symbol), which works like this:


-- define a variable called sum to be a function which computes the sum of two given values:
sum = (\x y -> x + y)

And use functions like this:


-- define a variable called ten to be the result of sum() applied to 5 and 5.
ten = sum(5, 5)

If you call functions with fewer arguments than that they require the result will be a function which takes as many arguments as needed to compute the original function's result. The arguments you supply are ordered from left to right, i.e the left most argument is the first one supplied. For example:


-- define a variable to be the result of calling sum() with only one argument (the first)
plus5 = sum(5)
-- define a variable to be the result of calling plus5() on 7 which is then the last (second) argument to sum():
result = plus5(7)
-- result == 12.


You end a branch of your algorithm using the keyword return and the name of the variable or a constant you want to return. This is so I know where to look for your actual computed answer. To clarify, since you will be calculating a new point, the return lines should either look like:


return point(my-x-coordinate,my-y-coordinate)
, or:


return my-result



Suppose now you are given three points, let's call them A, B, C. The three make an angle ACB which is not 180°. Additionally, d(A,B) is nonzero, d(B,C) is non zero and d(A,C) is non zero as well. The algorithm I am looking for will compute a fourth point named D which lies on the bisector of this angle ACB. I am not looking for a name, I am looking for an actual implementation which we can use to compute it.

This is purely about reasoning, it requires only a minimal amount of math knowledge. It is not actually very difficult, but it should hopefully prove quite satisfying to come up with a solution that works. I suggest keeping the answers in spoilers ([spoil]) tags until we find one which does the trick.

drone
08-02-2011, 00:37
Is this what you wanted?
if (d(A,C) < d(B,C))

shortLegPoint = A
longLegPoint = B
else

shortLegPoint = B
longLegPoint = A


normalizeRatio = d(shortLegPoint,C) / d(longLegPoint,C)
normalizePoint = point( ( (x(longLegPoint) - x(C) ) X normalizeRatio) + x(C), ( (y(longLegPoint) - y(C)) X normalizeRatio) + y(C) )
D = point( ( (x(normalizePoint) + x(shortLegPoint) ) / 2), ( (x(normalizePoint) + x(shortLegPoint) ) / 2) )
return(D)

Tellos Athenaios
08-02-2011, 03:54
Almost. Your approach is sound, but you made a typo which renders your calculations a bit worthless.

drone
08-02-2011, 04:24
Not a typo, a cut/paste error. I find I'm doing that a lot lately when coding...
if (d(A,C) < d(B,C))

shortLegPoint = A
longLegPoint = B
else

shortLegPoint = B
longLegPoint = A


normalizeRatio = d(shortLegPoint,C) / d(longLegPoint,C)
normalizePoint = point( ( (x(longLegPoint) - x(C) ) X normalizeRatio) + x(C), ( (y(longLegPoint) - y(C)) X normalizeRatio) + y(C) )
D = point( ( (x(normalizePoint) + x(shortLegPoint) ) / 2), ( (y(normalizePoint) + y(shortLegPoint) ) / 2) )
return(D)

Tellos Athenaios
08-02-2011, 04:36
Your turn, then.

drone
08-02-2011, 20:55
The Delta Tau Chi Deathmobile is heading full steam at the mayor's grandstand during the Homecoming parade. As they approach, the Deltas yell "Ramming Speeeeeed", tailing off with a pitch of C5 (523.25 Hz). If Dean Wormer hears the pitch as D5, how fast is the Deathmobile traveling?

Assume a dry fall day in Faber (roughly sea level) with no wind and a temperature of 15C.

Kralizec
08-02-2011, 22:35
Assuming that D5 means 623.25 Hz (not sure about this one)
If the speed of sound is 1224.995 Km/h,
(speed was calculated with the help of http://www.sengpielaudio.com/calculator-speedsound.htm )

then
623.25 x (1224.995 : (1224.995 - ?)) = 523.25
1224.995 : (1224.995 - ?) = 1,1911132345914954610606784519828
1224.995 - ? = 1028,445461291616526273565984758
? = 196,549538708383473726434015242 km/h

Correct?

drone
08-02-2011, 23:26
I think you are computing for D#5. D5 is 587.33Hz

Kralizec
08-02-2011, 23:48
Oops. That's not the only mistake I made last attempt.


133.6517456 km/h?

Drunk Clown
08-03-2011, 00:21
You guys are such nerds.

drone
08-03-2011, 00:47
Your turn, Krazilec. :bow:


You guys are such nerds.
:smug:

Arthur, king of the Britons
08-03-2011, 15:53
You guys are such nerds.

:yes:

Major Robert Dump
08-03-2011, 16:28
I know how to make meth

Kralizec
08-03-2011, 16:48
Okay...

Lesions on certain parts of the left hemisphere of the brain can cause aphasia. Explain why the same injuries can impair the ability to use sign language in deaf people, even though spatial/visual orientation is centred in the right hemisphere.

Cute Wolf
08-03-2011, 17:19
for most human brain structures:

the logical aspects of language control is located on broca and wernicke areas on the left hemisphere at the brain. presence of lesions at those areas will inhibit coordination of communication logic with the visual aspect in the right hemisphere. that means the visual stimuli can be received, but cant be processed

Kralizec
08-03-2011, 17:57
Hmm, I'm only a layman in this area (read a good book about it recently though, hence this question) but it seems to be incorrect.

Crucially, lesions in the right hemisphere of the brain wich causes visual/spatial disorientation do not affect a deaf person's ability to use sign language.

Tellos Athenaios
08-03-2011, 18:56
Yes, but there is a difference between general visual impairment and language impairment (aphasia). Depending on the precise part of the brain damaged it differs from the ability to coordinate your muscles to produce the language (motor aphasia), to the ability to understand formal language communication, to the ability to articulate your thoughts in whatever the medium of choice (i.e. signs, written forms, spoken).

For instance aphasia might make it very hard for a deaf person to remember what the signs mean, since the logical link between meaning and the memory of a sign are controlled by the affected part of the brain.

--- This is all just distilled from skimming Wikipedia. Would be interested to see this corrected by someone who does know what he is talking about.

Kralizec
08-03-2011, 20:25
Yes, but there is a difference between general visual impairment and language impairment (aphasia).

Yes, there is. That's the whole point of the question.

Tellos Athenaios
08-03-2011, 22:12
Yeah, what I'm saying is that sign language is still language and is still processed by the parts of the brain responsible for language & communication. Crucially, it has nothing whatsoever to do with spatial awareness: people can read text which is written upside down (and in some people actually are better at reading text upside down than the normal way up), but you will have far more difficulty with text which is rotated 180° because it appears backwards. (I guess because the shape is not vertically mirrored when text is rotated 180° your ability to scan the text for shape is effectively defeated as your scanning relies on direction of text flow.) By contrast detecting rotation is paramount to your spatial awareness, since your brain tends to defer to what your eyes report when it determines your own position and orientation within the world.

It's seems a bit like how people can recognise faces alright but still not recognise their mother if the part which controls for attaching emotions to images is damaged. Thus the emotions & memories of “I know her, that's my mum” is never triggered when they see their mother and therefore they will demand to know who is this woman and what is she doing here when their mother pays them a visit in hospital.

EDIT: I'm guessing that the brain simply “routes” relevant information to the language part of the brain in parallel when it is in communication mode. That is, when you expect to see something “readable” your brain make sure that the information which comes from your eyes is also passed on to your language bits at the same time as it is passed on for processing other visual cues. (It would also seem a rather big liability to rely on serial processing of images as a species, imagine driving a car and having to read every single road sign instead of being able to discard half of them and focus on what is actually happening on the road out of habit.)

Kralizec
08-03-2011, 22:42
Correct.

Visual/spatial functions of the right hemisphere are mostly perceptual. With sign language, signs are incorporated into a formal system (more specifically, a language) which is imbedded into the left hemisphere of the brain. People who have sign language as their primary language are subject to the same kind of language disorders as those who use spoken language; such as Broca's or Wernicke's aphasia, which are caused by damage to (parts of) the left half of the brain.
http://www.lifeprint.com/asl101/pages-layout/neurolinguisticsofasl.htm

"Signers" affected with aphasia do not lose their ability to make and interpret non-linguistical gestures. Conversely, loss of these functions (seated in the right hemisphere) do not affect a signer's ability to interpret or make linguistical signs. For example, a signer might lose the ability to interpret simple gestures like a shrug or waiving a fist, while retaining the ability to interpret complex linguistical gestures.
In other words, the ability to make or interpret linguistical gestures is largely, if not completely independent from other visual/spatial functions of the brain.

Most of the info is taken from Oliver Sacks' Seeing voices.
See also:
http://www.ncbi.nlm.nih.gov/pubmed/6668233

Your turn, Telly :bow:

a completely inoffensive name
08-04-2011, 07:56
The Delta Tau Chi Deathmobile is heading full steam at the mayor's grandstand during the Homecoming parade. As they approach, the Deltas yell "Ramming Speeeeeed", tailing off with a pitch of C5 (523.25 Hz). If Dean Wormer hears the pitch as D5, how fast is the Deathmobile traveling?

Assume a dry fall day in Faber (roughly sea level) with no wind and a temperature of 15C.

I didn't know how to figure this one out, but I am very interested in the principles behind it and the math to solve it broken down. I take it you have to exploit the doppler effect to figure out the speed?

gaelic cowboy
08-04-2011, 11:10
I didn't know how to figure this one out, but I am very interested in the principles behind it and the math to solve it broken down. I take it you have to exploit the doppler effect to figure out the speed?


http://en.wikipedia.org/wiki/Doppler_effect

http://en.wikipedia.org/wiki/Frequencies_of_notes

it's all there just scroll down page all you need then is the speed of sound at 15c in the medium in this case dry fall air.

f=((v/v-vs)*f0) rearrange it to get vs on it's own

v = velocity of waves in the medium at 15c in this case dry fall air is the medium (vs negative cos it's moving toward observer)
vs= velocity of the source
vr= velocity of the observer it's zero so can be ignored
f= detected frequency = d5
f0= actual frequency = c5

I haven't done any of this in a long long time since first or second yr year engineering science, so I cant claim I remember it well I got it from wiki too.

Tellos Athenaios
08-05-2011, 03:29
This is just one I don't know myself: why do adult cats meow? They don't do it towards other cats, they only meow towards humans.

Veho Nex
08-05-2011, 03:49
God

drone
08-05-2011, 03:58
GodI'm fairly certain cats don't believe in God. In a cat's mind, they are the only omnipotent beings around. :yes:

gaelic cowboy
08-05-2011, 23:44
well according to wiki
A meow is a sound used by cats to signal a request to their mother or owner. Adult cats do not normally meow to each other, and so the meowing to human beings that domesticated cats exhibit is likely partly an extension of the use by kittens of this plaintive signal

From what I can make out because we keep cats as pets those cats continue using meowing like a kitten to get attention from the mother/owner.

http://en.wikipedia.org/wiki/Meowing#Meowing

Ibrahim
08-06-2011, 06:45
This is just one I don't know myself: why do adult cats meow? They don't do it towards other cats, they only meow towards humans.

I was going to answer that, but gaelic cowboy beat me to it. :shrug:

If I may ask: how does an anatomist (for crocodiles and birds) determine the size of an animal's muscles, based on its bones? I've always tried to figure it out, but resources on that are shockingly few here.

gaelic cowboy
08-06-2011, 10:19
I was going to answer that, but gaelic cowboy beat me to it. :shrug:

If I may ask: how does an anatomist (for crocodiles and birds) determine the size of an animal's muscles, based on its bones? I've always tried to figure it out, but resources on that are shockingly few here.

I dunno but have look at this (http://qilong.wordpress.com/2011/03/23/muscles-of-fossil-animals/)

http://www.priweb.org/ed/lol/invdinos.html


What did dinosaurs look like? Paleontologists can reconstruct the body of most dinosaurs using marks on the bones called "muscle scars." Muscle scars form where muscles attached to the bones by tendons and ligaments. The large the scar, the more massive the muscle. Although rare, dinosaur skin impressions give scientists an idea of what they looked like from the outside. Since pigments do not fossilize, nobody really knows what color dinosaurs were. Artists use the colors of modern dinosaur relatives (reptiles and birds), as well as those of other large animals to guess at the color of dinosaurs.

Right sounds like they use things like muscle scar plus no doubt the already quite large body knowledge on anatomy collected over the years, there pretty much making the most educated guess available I suppose.


Now I going to be a bit sneaky here and say I got two mwah ha ha


Here is my question

Rob the Robot Rover has landed on the planetoid Omicron Persei 8 back on Earth the guys at Nasa are trying to work out the mass of said planetoid. Robs sensors are detecting that the 1kg mass of Rob (1kg back on Earth) now weighs 1.6 Newtons on Omicron Persei 8. The planetoid has been mapped as having a diameter of 4000km and the gravitational constant is

6.7*(10^-11) Nm^2/kg^2

Crazed Rabbit
08-06-2011, 17:11
6.57E+21 slugs

Or, 9.59E+22 kg

Where;
W = mg
g=W/m

W = 1.6 N, m = 1 kg

g = 1.6 m/s^2

M = g * r^2 /G

r = 2000 km

G = 6.7*(10^-11) Nm^2/kg^2

M = 9.59E+22 kg

CR

gaelic cowboy
08-06-2011, 17:37
6.57E+21 slugs

Or, 9.59E+22 kg

Where;
W = mg
g=W/m

W = 1.6 N, m = 1 kg

g = 1.6 m/s^2

M = g * r^2 /G

r = 2000 km

G = 6.7*(10^-11) Nm^2/kg^2

M = 9.59E+22 kg

CR

On with the Show CR well done

Crazed Rabbit
08-06-2011, 19:31
:beam:

Alright, as you can't get The Code (http://www.asme.org/kb/standards) for free, I'll have to think a bit on what to ask while I go fishing this afternoon.

CR

Crazed Rabbit
08-10-2011, 06:42
Okay, sorry for the delay.

A torchship - a spaceship that accelerates or decelerates continually, with no coasting - is traveling from one space station to another space station. The space stations are fixed points in space and do not orbit anything. There are no nearby planets, or anything of large enough mass, to substantially affect the ship's journey.

This space ship is traveling from the first station, to the second station, and back again.

The torchship takes 353 70.6 days 34,928.2 seconds to travel the distance between the space stations. It's engines are on full power all the way, at 5 Gs (the crew are genetic supermen). It starts at rest at the first space station and comes to a complete stop at the other space station. It then makes the return journey in the exact same way.

So, it travels 353 70.6 days, or 1694 hours 34,928.2 seconds, with an engine capable of a constant 5 Gs of acceleration at full burn the whole time.

What is the total delta V of the ship, assuming it doesn't refuel at the second space station and is completely out of fuel when it returns to the first station? The delta V is the measure of the change in velocity of the ship over it's entire journey. So if a ship accelerated to 10 km/s and then was out of fuel, it would have a delta V of 10 km/s. It would have the same delta V if the ship accelerated to 5 km/s, then slowed back down to a stop (which is useful if you don't want your spaceship to go hurtling into the void with out ever slowing down).

Bonus question; what is the first space station going to look like when the torchship returns?

CR

Papewaio
08-10-2011, 06:59
I thought as it's displacement is zero and its speed is zero its delta V would be zero.

Crazed Rabbit
08-10-2011, 07:24
Nope. Delta V is best described as how much a space ship can change it's velocity. Since the spaceship in this example increases and decreases it's velocity, it's that change that the Delta V represents. It's not a comparison of velocity at one point in time (before the ship starts traveling) to another (when the ship has reached the end of it's journey).

Also, 1 G = 9.81 m/s

CR

Papewaio
08-10-2011, 11:39
So the total change in velocity as if it had moved in a straight line for the entire time.

Time = t = 353 days x 2 = 353 x 24 x 60 x 60 x2 seconds = 60,998,400 seconds
acceleration = a = 5G = 5 x 9.81m/s = 49.05 m/s
Initial velocity = u = o

v = u + (a x t)
v = a x t
v = 49.05 x 60,998,400
v = 2,991,971,520 m/s
v = approximately ten times the speed of light {299,792,458 m/s = c}.

So this tells us something is wrong... the max speed of the craft can only get to c (not 2.5c at any point) therefore the Change would be upto c back down to zero, upto c and backdown to zero.

So a maximum Delta V of 4c by the theory of relativity.

And the station would look the same as the craft should be stationary.

Crazed Rabbit
08-10-2011, 15:18
Whoops, you're right. With 5 Gs for that long the craft would exceed the speed of light. But you're a bit off on how much it would exceed it.

Ok, new data points; The craft still accelerates at 5 Gs, but only travels for 70.6 days, or 1694.4 hours 34,928.2 seconds.

CR

Tellos Athenaios
08-10-2011, 22:52
The bonus question is pretty easy: that space station will be either no more or it will have moved away quite a bit (or a combination of both). 5G acceleration? That's 49.0m/s/s. Given that this ship travels by emitting particles through an exhaust, the fact is that this ship moves much the same as how a rocket leaves the surface of the earth: it pushes itself away by means of particles traveling at very high speeds. So assuming an ideal world where space can be represented as a vacuum (though it is not), that ship will be exerting a continuous force equal to its own mass times 49 in Newton (5G acceleration). IOW if the ship weights 1kg, the force will be 49N. If it weighs one tonne, it will be 49kN of continuous force exerted on the space station.

... Guess what 49 tonnes of weight do to your space station when it falls/collides on top of it/head on, on earth?

Crazed Rabbit
08-11-2011, 15:10
Tellos gets the bonus right!

Here's a hint for the question; all you need to find the answer is the distance traveled. And you can find that with the data already there.

CR

Papewaio
08-12-2011, 03:01
Only if the station provides a shape that can be pushed against and the plume isn't ionized.

You could have a doughnut shaped station and the plume go through it.
You could have the space ship offset to it's natural stationary point which would be a Lagrange zone.

Afterall if you're smart enough to design such a ship you're smart enough not to hold the firecracker... Mind you rocket scientists aren't the smartest lot just look at the epic failure in converting between imperial and metric.

As for the propulsion it would make sense to emitt as highly energized particles as possible... So an ion drive would be a possible choice. Using that and magnetic fields on the station you could not only shield the station from an ion drive you probably could use it to collect some energy and redirect the plume in a manner that keeps it in place much like a spike... of course KISS and just don't start behind the spaceship would be the simple choice.

Crazed Rabbit
08-15-2011, 22:10
Papewaio is right that there are ways to avoid destroying the space station. Tellos' answer was the one I was looking for though.

A BIG hint; google "torchship" and look for the atomic rocket site.

CR

Louis VI the Fat
08-15-2011, 22:48
6.57E+21 slugs

Or, 9.59E+22 kg

Where;
W = mg
g=W/m

W = 1.6 N, m = 1 kg

g = 1.6 m/s^2

M = g * r^2 /G

r = 2000 km

G = 6.7*(10^-11) Nm^2/kg^2

M = 9.59E+22 kg

CRExcuse me, but isn't http://www4.ncsu.edu/%7Ekaltofen/top10eqs/img7.gif so that http://www4.ncsu.edu/%7Ekaltofen/top10eqs/img8.gif and therefore http://www4.ncsu.edu/%7Ekaltofen/top10eqs/img10.gif ?

Papewaio
08-16-2011, 03:23
So without Google and doing this over twenty years ago:
gravitational attraction, integral of a function (the area under the line between two points) and the Alpha Decay of Uranium-238 into the isotope Thorium-234...

True you could use gravitational attraction to slingshot a uranium reactor powered (atomic) torchship around a planet to increase speed and that would involve I think Keplers emperical function (area of an arc/sweep of a orbiting object) modified by the acceleration... so Louis is right again.:yes:

gaelic cowboy
08-17-2011, 22:23
Excuse me, but isn't http://www4.ncsu.edu/%7Ekaltofen/top10eqs/img7.gif so that http://www4.ncsu.edu/%7Ekaltofen/top10eqs/img8.gif and therefore http://www4.ncsu.edu/%7Ekaltofen/top10eqs/img10.gif ?

Ah how shall I put this hmm ah

NO

Louis VI the Fat
08-18-2011, 01:40
Ah how shall I put this hmm ah

NOWhat's Nobelium (http://education.jlab.org/itselemental/ele102.html) got to do with it?

Crazed Rabbit
08-18-2011, 03:43
Nothing, Louis. He was clearly referring to Nitrogen and Oxygen. :rolleyes:

For the equations to answer to my question, go here (http://www.projectrho.com/rocket/torchships.php#id--Brachistochrone_Equation), and then here (http://www.projectrho.com/rocket/torchships.php#id--Delta-V).

CR

Louis VI the Fat
08-18-2011, 03:52
Nothing, Louis. He was clearly referring to Nitrogen and Oxygen. :rolleyes:I KNEW THAT I WAS JUST TESTING IF YOU KNEW




Louis - smarter then yuo

Papewaio
08-18-2011, 04:07
LOL that's funny because it's clearly Nitrous Oxide which is laughing gas.

Hamata
08-20-2011, 18:11
nevermined

Cute Wolf
08-21-2011, 11:15
LOL that's funny because it's clearly Nitrous Oxide which is laughing gas.

it's N2O not NO

Crazed Rabbit
08-21-2011, 17:15
So I messed up the time value, it's actually 34,928.2 seconds.

These are the equations we want to use;

T = 2 * sqrt[ D/A ]

where

T = transit time (seconds)
D = distance (meters)
A = acceleration (m/s2)
sqrt[x] = square root of x

and

DeltaV = 2 * sqrt[ D * A ]

You just need to find distance then plug that into the DeltaV equation.

CR

Drunk Clown
08-21-2011, 18:13
it's N2O not NO

It's N2O not N2O.