All Questions
47
questions
0
votes
1
answer
21
views
Can we treat the entire mass of the spheroid as being concentrated at its center?
I know that to find the gravitational force between two objects, if either of them is a sphere, we can assume its mass to be concentrated at its center and use the formula for gravitational forces for ...
- 69
8
votes
5
answers
290
views
What is the gravity in the center of Earth?
Let's suppose the earth is a perfect sphere and let's ignore its rotation and movement.
What would happen if I would be in the center of the earth? Would the gravity be zero in any direction so I ...
- 209
2
votes
2
answers
356
views
Is $F=mg$ derived from Newton's law of universal gravitation $F=Gm_1m_2/r^2$?
If so, that means gravity is only 9.8 m/s^2 at the surface of the earth?
- 21
1
vote
1
answer
88
views
What would happen if the Earth rotated at the rate required to achieve orbit at its radius? I.e ~7k m/s instead of ~460 m/s
To achieve a circular orbit, you need to have a velocity of $$v = \sqrt{Gm/r}$$ which is about 7 km/s at the Earth’s radius, but the Earth’s rotational speed is only about 460 m/s (by taking the ...
- 111
1
vote
2
answers
267
views
How close can Jupiter be to Earth without making Earth unhabitable? [closed]
How close can Jupiter be to Earth without making Earth unhabitable? What's the closest distance possible? Can Jupiter be twice or three or four times as close to Earth as Mars without having any ...
- 791
0
votes
2
answers
51
views
How does formula for universal gravitation between mass $M$ and mass $m$ collapse to $mg$ on Earth? [duplicate]
Can anyone give a mathematical demonstration of this? I assume it has to do with the fact that Earth’s mass is much bigger than the mass of any object on Earth, but I think it would be interesting to ...
- 556
27
votes
6
answers
16k
views
Does gravity get stronger the higher up you are on a mountain?
So I saw this article stating that gravity is stronger on the top on the mountain due to there being more mass under you however I have read some questions other people have asked and most of the ...
0
votes
1
answer
69
views
Will the weight further increase while going inside the Earth? [duplicate]
Our weight is more at the pole than at the equator (because it is closer to the center).
Does that mean if we go down into the earth (some kind of bore), will our weight increase further?
I remember ...
- 51
1
vote
1
answer
2k
views
Why does the trend of gravitational field of Earth is like this ( the graph below)? [duplicate]
I think that, since Earth is spherical, the amount of mass in the upper half of Earth should be the same as the second half, therefore, if the strength of gravitational field increase linearly from ...
- 37
-1
votes
3
answers
2k
views
The acceleration in Earth's gravity
The acceleration in earth's gravity is $9.807 m/s^2$ at my location. But is this value uniform in the entire earth? For example in the inner core or outer core. What is the acceleration in the center ...
1
vote
1
answer
214
views
The Earth's Equatorial Bulge [duplicate]
It is stated that the Earth is a 'squashed sphere' due to the very slight bulge at the equator. (Thought in reality it's such a small difference, it's essentially spherical)
Typical values:
...
- 11
0
votes
4
answers
7k
views
What is acceleration due to gravity at the centre of the earth? [duplicate]
When I asked my teacher that what is the acceleration at the centre of earth, he replied that it is 0 as when we move inside the earth, the effective mass decreases i.e. the mass that exerts ...
- 592
0
votes
1
answer
2k
views
Gravitational force on object inside Earth
When we find the gravitational field on an object that lies inside Earth we simplify the problem by considering the sphere whose radius is the distance of the object from the center of Earth. We use ...
1
vote
0
answers
27
views
Estimation of Equatorial Bulge of the Earth [duplicate]
My dynamics lecture notes repeat the Earth's equatorial bulge can be approximated as:
$$ \approx \frac{\Omega^2R}{g} \approx \frac{1}{300} $$
(Do they mean R/300?)
They also include statements like:
...
- 683
0
votes
0
answers
32
views
Gravitational potential energy on the Earth's surface [duplicate]
We assume that gravitational potential energy at a height $h$ from the Earth's surface is $mgh$. Is that accurate or only approximately correct ?
Here is my approach.
On the surface of the Earth,
$...
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