plotting the bloody TRAJECTORY of a satellite... (1 Viewer)

[gordo]

yeh last time i checked, asking students to plot the trajectory of planets and satellites wasn't in the syllabus

 

[Jezzabelle]

grrr i thought the test was ok

then i come on here and remember all these hideous questions!!

umm i thought it was referring to syllabus point about launching of satellites and wat direction they are launched to get boost velocity.

so i drew it launching in an easterly direction ahead of the earth.
and for the december bit. i cut up my orbit of earth into 12 sections, like a cake (mm cake) and worked out that.. this sector is june so by counting.. this sector is december... so therefore. etc etc.

 

[gordo]

u didn;t know which way was east though

they gave u the north pole, east coule be any direction around it (there are no directions in space)

and its certainly not in the syllabus to know if the planets orbit clockwise or anticlockwise around the sun...
the question was stupid
part ii of it was normal, part i was irrelevant (i.e. plotting the shortest course for the satellite from earth to mars taking into account their orbits and rotation...thats for space engineers)

 

[Jezzabelle]

u didn;t know which way was east though

they gave u the north pole, east coule be any direction around it (there are no directions in space)

and its certainly not in the syllabus to know if the planets orbit clockwise or anticlockwise around the sun...
the question was stupid
part ii of it was normal, part i was irrelevant (i.e. plotting the shortest course for the satellite from earth to mars taking into account their orbits and rotation...thats for space engineers)

yeh.. the michael jordan thing, this one, the solar cells, the centripetal force on road...

grrrrrr not so confident anymore

 

[Gomer]

You were looking from the top of the Earth, so you had to draw a line from the inside of the planet, to the left (i think the earth orbits around the sun in that direction?) and you had to assume that Mars in december would be in line with that trajectory.

Because for interplanetary they launch in easterly direction, and in the same direction the earth is moving with reference to the sun. I think... Then you draw a circle on earths orbit on the other side of the sun as that is where it would be in 6 months time. *shrugs*

It was a dumb question, i never knew drawing trajectories was in the syllabus.

-- Gomer

 

[BillyMak]

You can't say from that diagram what way the earth was spinning, because if you were to look at it from the opposite side everything would be the opposite.

 

[fush]

yea that was a bitch of a question, i just draw the sun and mars in the same positions on the other side of the sun...so on the top and i drew a trajectory that went from one to the other, i specified that the earth spins from west to east too

 

[speersy]

yea that was a bitch of a question, i just draw the sun and mars in the same positions on the other side of the sun...so on the top and i drew a trajectory that went from one to the other, i specified that the earth spins from west to east too

yeah i did the same and also specified which way i took earth to be orbiting around the sun

 

[gordo]

i just looked up on the net
when looking from a northerly direction down, the planets rotate countr clockwise, i.e. to the right

screw that
i did to the left

how the fuk are we supposed to know that
such a dumd exam and i remain adament at that

 

[BillyMak]

You can't just draw Earth and Mars on the opposite side of the planet. Remember that Mars has a larger orbit so it has a longer period than earth (r³=kT²).
In the time the earth travels half of it's orbit, judging by the diagram Mars would have only orbitted about 1/3 of the way around.

 

[Rorix]

Mars' orbit is about 4 years I think.

Yeah, this question was pretty crap.

 

[gordo]

mars orbit is 665 days

we shoudl all complain and get the exam cancelled

 

[mr_guy99493]

mars orbit

from the diagram, i assumed that mars radius around the sun is about twice that of earth, - i know its not,
then using r^3 =kT^2, and comparing the length of the arc that earth travelled, could figure out mars was bout 1/6 the way around from where it started, or 1/(2xsqrt8)

 

[Shuter]

I had my drawing with the earth basically on the other side, and mars was just above being directly to the right of the sun.

Then I had the rocket launching from the part of the leftmost point of earth, and making a slight small spiral then a strait line to Mars. I launched from this point to gain the relative velocity boost ffrom both Earth's rotation and it's orbit around the sun. I believe it was correct.

 

[CrashOveride]

i did pretty much wat shutter said

 

[gordo]

but how did u know the planets orbitted counter clockwise wen viewed from a northerly plane

or was it a guess?

 

[Jase]

Well, it doesn't really matter which way you took the Earth to orbit, since you should get it exactly half way across... then mars you have a 50% chance of gettign right... and then another 50% chance of getting the spin right, and then an undefined factor in actaully drawing the correct path..
in other words it fucking sucked.

 

[CrashOveride]

i just wana say, its over, who cares now. ciao

 

[Shuter]

but how did u know the planets orbitted counter clockwise wen viewed from a northerly plane

or was it a guess?

Dunno, year 9 science? It just seemed logical to me, I was pretty sure it went that way.

 

[grimreaper]

I assumed it went in a clockwise direction... and the satellite went in an elliptical sort of motion in transferring from the Earth's radius from the sun to the Mars distance from the sun