Zenarthra
Badges: 3
Rep:
?
#1
Report Thread starter 6 years ago
#1
http://filestore.aqa.org.uk/subjects...2-QP-JUN12.PDF

Q 4biii) I dont understand what the question means.

Could someone help please?

Thanks!
0
reply
uberteknik
  • Study Helper
Badges: 21
Rep:
?
#2
Report 6 years ago
#2
(Original post by Zenarthra)
http://filestore.aqa.org.uk/subjects...2-QP-JUN12.PDF

Q 4biii) I dont understand what the question means.

Could someone help please?

Thanks!
It's asking for an explanation why the gravitational potential due to that of the sun does not need to be taken into account when calculating the minimum energy needed to move the spaceprobe from the earth to point X.
0
reply
Zenarthra
Badges: 3
Rep:
?
#3
Report Thread starter 6 years ago
#3
(Original post by uberteknik)
It's asking for an explanation why the gravitational potential due to that of the sun does not need to be taken into account when calculating the minimum energy needed to move the spaceprobe from the earth to point X.
Ahh ok thanks and hi!
Well would i be right in saying:
The gravitation potential due to the sun on the earth is given by V=-GM/r
As the distance from the sun to the earth is so great, the gravitational potential at earth due to the sun will be negligible.
Considering a very small number of V multiplied by the distance from earth to X, giving the extra work done due to the gravitational potential of the sun. This value is so insignificant than that of the work needed to move a space probe through dV of gravitational potential due to the earth, that it does not affect the minimum energy.

thanks.
0
reply
uberteknik
  • Study Helper
Badges: 21
Rep:
?
#4
Report 6 years ago
#4
(Original post by Zenarthra)
Ahh ok thanks and hi!
Well would i be right in saying:
The gravitation potential due to the sun on the earth is given by V=-GM/r
As the distance from the sun to the earth is so great, the gravitational potential at earth due to the sun will be negligible.
Considering a very small number of V multiplied by the distance from earth to X, giving the extra work done due to the gravitational potential of the sun. This value is so insignificant than that of the work needed to move a space probe through dV of gravitational potential due to the earth, that it does not affect the minimum energy.

thanks.
Not quite.

Think of the F = GmM/r2 relationship and the gravitational field in the vicinity of the earth due to the sun. It does not change significantly because the distance change from the earth to the moon is around 0.3% of the distance to the sun. Hence the force difference at that distance changes by an insignificant amount.
0
reply
Zenarthra
Badges: 3
Rep:
?
#5
Report Thread starter 6 years ago
#5
(Original post by uberteknik)
Not quite.

Think of the F = GmM/r2 relationship and that the because the field in the vicinity of the earth does not change significantly because the distance change from the earth to the moon is around 0.25% of the distance to the sun and hence the force difference is the inverse square of that.
Ahh ok, but how to explain in terms of gravitational potential?
0
reply
Stonebridge
Badges: 13
Rep:
?
#6
Report 6 years ago
#6
The gravitational potential difference, due to the Sun, between the Earth and Moon is negligible for the same reason.
0
reply
Zenarthra
Badges: 3
Rep:
?
#7
Report Thread starter 6 years ago
#7
Thanks to both of you!
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Back
to top
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

Have you experienced financial difficulties as a student due to Covid-19?

Yes, I have really struggled financially (44)
18.41%
I have experienced some financial difficulties (68)
28.45%
I haven't experienced any financial difficulties and things have stayed the same (91)
38.08%
I have had better financial opportunities as a result of the pandemic (30)
12.55%
I've had another experience (let us know in the thread!) (6)
2.51%

Watched Threads

View All
Latest
My Feed