the satelite Q? (1 Viewer)

[lordesf]

Hey do u all rmeber the 3 mark saellite Q? spomtjhing like descirbe the chnages in momemtum of the propulsion of satelites or somthing random?

wat was it i had no clue..

 

[dolbinau]

http://community.boredofstudies.org/showthread.php?t=190708

here is all the questions, now the one you want

19.

a) Explain the changes in momentum when a satellite fires its propulsion system. 3 marks

Basically, I wasn't sure

but I used P=MV and basically explained by the conservation of momentum P(before)=P(after). I don't know if that's right, it's not really that accurate. So basically change in mass by decrease in fuel = increase in velocity = same momentum.

 

[pdoueihi]

http://community.boredofstudies.org/showthread.php?t=190708

here is all the questions, now the one you want



Basically, I wasn't sure

but I used P=MV and basically explained by the conservation of momentum P(before)=P(after). I don't know if that's right, it's not really that accurate. So basically change in mass by decrease in fuel = increase in velocity = same momentum.

well i used conservation of momentum, ie change in momentums (delta P fual = delta P rocket) then i used (delta Ft fual = delta Ft rocket), and i cancelled the 't's so its like newton's third law

mine was pretty similar

 

[dolbinau]

Yeah same concept I think (hope).

 

[Kearnzo]

I was not confident with this question...

I remembered using equations in class that had the momentum of the rocket and gases. How does the burning of fuel come into it?

 

[Js^-1]

I didn't use any equations, which was probably a mistake, but I said that when the rocket is at rest, momentum is conserved, so when the gases are combusted and ejected at high velocity in one direction, then the rocket must move in the opposite direction to conserve momentum. The gases are ejected with huge velocity, but individually they have little mass, whereas the rock has a huge mass, and therefore moves off slowly in the opposite direction.

Not very eloquent or in-depth, probably wont get many marks for it.

 

[dolbinau]

It's 3 marks, It'll be hard not to get 1 mark IMO.

 

[leisl1990]

this question is infact very confusing.
satellite does not lauch by burning its own fuel but it s carried by a rocket or something.
so i thought, it was just about a orbiting satellite firing some boosters to either increase or decrease its speed.
did anyone do the same ? i was just thinking in the exam.

 

[lordesf]

this question is infact very confusing.
satellite does not lauch by burning its own fuel but it s carried by a rocket or something.
so i thought, it was just about a orbiting satellite firing some boosters to either increase or decrease its speed.
did anyone do the same ? i was just thinking in the exam.

YES EXACTLY wat i thought in the exam! The 1st thing tht poppd up was the rocket launch with mometum conserved but it asked for :satellite propulsion(WTF is tht?)

so i figured it had to do with some manuvre while orbiting

so i said momentum chnage as P=mv as velocity chnages (porbbaly wrong.. now )