• Best of luck to the class of 2024 for their HSC exams. You got this!
    Let us know your thoughts on the HSC exams here
  • YOU can help the next generation of students in the community!
    Share your trial papers and notes on our Notes & Resources page
MedVision ad

Geostationary Orbits (Q17) (1 Viewer)

Stopsign

Member
Joined
Sep 7, 2005
Messages
89
Location
Location!
Gender
Undisclosed
HSC
N/A
Post-exam hangover...The geosationary orbit question was worth 6 marks. That's alot and I'm ashamed of myself for not knowing this.

What were the forces acting on it whilst in orbit and re-entering?
 

RingerINC

BBoy OG Loc Gangsta
Joined
Jan 22, 2005
Messages
571
Location
In The Circle
Gender
Male
HSC
2006
Stopsign said:
Post-exam hangover...The geosationary orbit question was worth 6 marks. That's alot and I'm ashamed of myself for not knowing this.

What were the forces acting on it whilst in orbit and re-entering?
all i could think of were gravity and drag up in orbit... i said drag was minimal compared to that of leo.

And during reentry the whole g-forces speel on people getting knocked the fuck out, also gravity.

And i went into a bit on what a geo stat was at the beginning and what needs to be taken into account on re entry to minimise forces.
 

cjh

New Member
Joined
May 31, 2005
Messages
8
Gender
Male
HSC
2006
basically any orbit undergoes a centripetal force of gravitational attraction to the earth. there was also newtons gravitational force of attraction between the earth and the spacecraft. as well as the frictional forces due to the shuttle re-entering the earths atmosphere.

ohh plus, the g-forces acting on the space travelers, etc


there were a lot of forces
 

Ioup

Member
Joined
Oct 24, 2005
Messages
73
Gender
Male
HSC
2006
Tricky.lol
I said since it's in unifrom circular motion, gravity=centripetal force.
And yeah basically the same as what others have said here.
 

myeewyee

New Member
Joined
Aug 21, 2005
Messages
28
Gender
Male
HSC
2006
And a momentary thrusting force to get it out of geostationary orbit, i think
 

hyparzero

BOS Male Prostitute
Joined
Sep 10, 2005
Messages
246
Location
Wankersville
Gender
Female
HSC
2006
Marking Scheme:

Mentioning Gravity .... 1 Mark
Mentioning centripetal acceleration is perpendular to earth's gravity... 1 Mark
Mentioning thrusting force to throw spacecraft off the orbit... 1 Mark
Mentioning that during re-entry, Spacecraft subject to DECELERATION forces ... 1 Mark
Saying that the effects of gravitational pull is neglible during re-entry ... 1 Mark
Conversion of Kinetic Energy to heat during deceleration due to drag forces... 1 Mark
 

helper

Active Member
Joined
Oct 8, 2003
Messages
1,183
Gender
Male
HSC
N/A
They also may be after the retarding force mention by myeewyee to slow you down and result in you losing altitude.
They will also be looking for the effects of these forces as it is analyse. So at a guess they will probably be looking for you to describe three forces and then describe the effect they have on the space craft.
 

shinji

Is in A State Of Trance
Joined
Feb 2, 2005
Messages
2,733
Location
Syd-ney
Gender
Male
HSC
2006
i thought the question asked the forces acting on the Spaceship .. not the people.

anyway, forces i described:
-> centripetal force
-> velocity of the spacecraft
-> acceleration towards re-entry
-> friction caused by atmosphere tht acts upon the earth .. .

i forgot to mention g-forces.
 

sja

dingleberry
Joined
Mar 17, 2006
Messages
201
Gender
Male
HSC
2006
it was specific to the stage where they were orbiting around the earth. the only two forces you had to bullshit about were earth's gravity and centripetal force - stating that velocity is perpendicular to the gravity as it goes around

they didn't ask for the re-entry because it's already been asked in previous years and wanted to expand the questions
 

helper

Active Member
Joined
Oct 8, 2003
Messages
1,183
Gender
Male
HSC
N/A
sja said:
they didn't ask for the re-entry because it's already been asked in previous years and wanted to expand the questions
Parts of a space mission involve a spacecraft spending time in geostationary orbit and then returning safely to earth

Analyse the forces acting on this spacecraft during these parts of the mission
 

suchet_i

derka derka
Joined
Oct 25, 2005
Messages
127
Location
still trying to find a place to live at
Gender
Male
HSC
2006
another force is thrust coz they use rocket boosters to slow down the re-landing.. then u can talk about conservation of memontum with that and stuff. i also talked a bit about weightlessness and explained that
 

hyparzero

BOS Male Prostitute
Joined
Sep 10, 2005
Messages
246
Location
Wankersville
Gender
Female
HSC
2006
shinji said:
-> acceleration towards re-entry
During re-entry, space craft SLOWS DOWN not SPEED UP. thus, its deceleration.

Hope you wrote that.


suchet_i said:
another force is thrust coz they use rocket boosters to slow down the re-landing.. then u can talk about conservation of memontum with that and stuff. i also talked a bit about weightlessness and explained that
No spacecraft has EVER used rocket boosters to slow themselves down for landing...
 

Bricnic

Lookatmy Member
Joined
Jul 16, 2005
Messages
56
Location
Murwillumbah
Gender
Male
HSC
2006
I talked about:
*the lack of a weight reaction force while in orbit, as the craft was in constant freefall
*the minimal friction due to the very thin atmosphere at that height
*the slight increase in g as the craft approaches Earth
*the gradually increasing friction due to increasing density of atmosphere, and finally
*the weight reaction force being restored to the craft as it touches down, giving it a standard G force that all objects on the surface experience.
 

Mumma

Member
Joined
May 19, 2004
Messages
586
Location
Sydney
Gender
Male
HSC
2006
hyparzero said:
Marking Scheme:

Mentioning Gravity .... 1 Mark
Mentioning centripetal acceleration is perpendular to earth's gravity... 1 Mark
Mentioning thrusting force to throw spacecraft off the orbit... 1 Mark
Mentioning that during re-entry, Spacecraft subject to DECELERATION forces ... 1 Mark
Saying that the effects of gravitational pull is neglible during re-entry ... 1 Mark
Conversion of Kinetic Energy to heat during deceleration due to drag forces... 1 Mark
What does kinetic energy -> heat have to do with the forces experienced during re-entry and orbit? Why would that be part of the marking scheme?
 

hyparzero

BOS Male Prostitute
Joined
Sep 10, 2005
Messages
246
Location
Wankersville
Gender
Female
HSC
2006
Mumma said:
What does kinetic energy -> heat have to do with the forces experienced during re-entry and orbit? Why would that be part of the marking scheme?
the question said ANALYSE, so you'll need to specify WHAT forces acted on the space craft, WHY they acted the way they did and HOW these forces played a part during re-entry.

Simply stating that there exists atmospheric drag isn't analysing - that's just outlining.
 

shinji

Is in A State Of Trance
Joined
Feb 2, 2005
Messages
2,733
Location
Syd-ney
Gender
Male
HSC
2006
During re-entry, space craft SLOWS DOWN not SPEED UP. thus, its deceleration.

Hope you wrote that.
well they have to accelerate to get into the earth's atmosphere don't they?
when they geti nto the earth's atmosphere, THAT'S when they'll slow down due to the friction.

i stand my ground. =]
 

zeek

Member
Joined
Sep 29, 2005
Messages
549
Location
ummmmm
Gender
Male
HSC
2006
hyparzero said:
No spacecraft has EVER used rocket boosters to slow themselves down for landing...
retrofiring?

Don't worry guys, i don't think you were meant to address every single force occuring because then that would be a waste of time. If you did the implications of the forces, e.g. g-forces => leads to unconsciousness blah blah and stuff like that you should still get marks for it because you're describing the implications of the forces (part of what ANALYSE means)
If you think you've addressed everything then you probably have... cheer up and dw :)
 

Mumma

Member
Joined
May 19, 2004
Messages
586
Location
Sydney
Gender
Male
HSC
2006
Man these exams are more about guessing about what the examiners want than answering the questions.
 

Roboooo

New Member
Joined
Sep 18, 2006
Messages
25
Gender
Undisclosed
HSC
2006
hyparzero said:
During re-entry, space craft SLOWS DOWN not SPEED UP. thus, its deceleration.

Hope you wrote that.




No spacecraft has EVER used rocket boosters to slow themselves down for landing...
actually they do

retrofire the rockets captain!
 

JhK89

Member
Joined
Mar 16, 2006
Messages
233
Gender
Male
HSC
2006
fuck i didnt read the question properly... only read the geostationary part..
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top