The Student Room Group

How stupid is this?

http://www.ocr.org.uk/Images/61757-question-paper-unit-g484-the-newtonian-world.pdf
http://www.ocr.org.uk/images/64639-mark-scheme-unit-g484-the-newtonian-world-january.pdf

Question 6c)
If i use the full answer from b which is 2.277x10^-20
Ill get 2461.8 m/s
roughly = 2.5km/s
They used the round answer...
So i wouldnt get the marks then?

Also
3aii) Explain why these satellites orbit above equator
Answer: so they stay above same point at all times
Like what?
Shouldn't it be because only at the equator time period = 24hours.

4aii)
Suggest 2 possible reasons why actual increase will be much lower than estimate?
Answer: Heat lost to structure of greenhouse
Heat lost to surroundings


THEY MEAN THE SAME THING!

For 6d)
Is it not correct to say gravitational field strength at the upper atmosphere is much weaker than at the surface of earth.
11km/s is for an object at the surface of earth.
Temp at upper atmosphere is 1100k, therefore provided KE for helium molecules.
I cant see any where on earths surface being 1100K so how could hedlium atoms escape from surface?
(edited 8 years ago)
Original post by Zenarthra
http://www.ocr.org.uk/Images/61757-question-paper-unit-g484-the-newtonian-world.pdf
http://www.ocr.org.uk/images/64639-mark-scheme-unit-g484-the-newtonian-world-january.pdf

Question 6c)
If i use the full answer from b which is 2.277x10^-20
Ill get 2461.8 m/s
roughly = 2.5km/s
They used the round answer...
So i wouldnt get the marks then?

Also
3aii) Explain why these satellites orbit above equator
Answer: so they stay above same point at all times
Like what?
Shouldn't it be because only at the equator time period = 24hours.

4aii)
Suggest 2 possible reasons why actual increase will be much lower than estimate?
Answer: Heat lost to structure of greenhouse
Heat lost to surroundings


THEY MEAN THE SAME THING!

For 6d)
Is it not correct to say gravitational field strength at the upper atmosphere is much weaker than at the surface of earth.
11km/s is for an object at the surface of earth.
Temp at upper atmosphere is 1100k, therefore provided KE for helium molecules.
I cant see any where on earths surface being 1100K so how could hedlium atoms escape from surface?


don't really know about the others, but for 6c), look in the 'guidance' box (second column of mark scheme) and it says 'Full credit to be given for the use of 2 x 10^-20 (J)from (b) giving v = 2.5 x 10^3 (ms-1 )', so you would get full marks for that answer :smile:
(edited 8 years ago)
Reply 2
Original post by Zenarthra
http://www.ocr.org.uk/Images/61757-question-paper-unit-g484-the-newtonian-world.pdf
http://www.ocr.org.uk/images/64639-mark-scheme-unit-g484-the-newtonian-world-january.pdf

Question 6c)
If i use the full answer from b which is 2.277x10^-20
Ill get 2461.8 m/s
roughly = 2.5km/s
They used the round answer...
So i wouldnt get the marks then?

Also
3aii) Explain why these satellites orbit above equator
Answer: so they stay above same point at all times
Like what?
Shouldn't it be because only at the equator time period = 24hours.

4aii)
Suggest 2 possible reasons why actual increase will be much lower than estimate?
Answer: Heat lost to structure of greenhouse
Heat lost to surroundings


THEY MEAN THE SAME THING!

For 6d)
Is it not correct to say gravitational field strength at the upper atmosphere is much weaker than at the surface of earth.
11km/s is for an object at the surface of earth.
Temp at upper atmosphere is 1100k, therefore provided KE for helium molecules.
I cant see any where on earths surface being 1100K so how could hedlium atoms escape from surface?


Geostationary satellites have to be above the equator specifically so that they do not move relative to an observer on the ground. The 24 hour time period is also required, but would be achieved by a satellite on any orbit so long as it has the correct radius. Basically, the reason it needs to be on the equator is that if it's not, it will drift up and down- drawing this out should convince you, but I can't explain it very well.

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