All Questions
Tagged with newtonian-gravity reference-frames
228
questions
57
votes
4
answers
13k
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What does the Moon's orbit around the Sun look like?
I'm curious as to what the Moon's orbit around the Sun looks like. If there's an answer, what's the intuition for it? Here are some things I'm assuming when trying to tackle this question:
The Moon's ...
- 751
46
votes
7
answers
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If the ground's normal force cancels gravity, how does a person keep rotating with the Earth?
When I am on earth, the weight of my body is countered by the reaction of the ground. So, there is no net force acting on me.
But I am spinning with earth. But if there is no centripetal force then ...
- 1,228
42
votes
3
answers
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If I drop a ball in an accelerating rocket, will it bounce? If so, how?
Einstein's equivalence principle says that you cannot distinguish between an accelerating frame or a gravitational field. However, in an gravitational field, if I drop a tennis ball, it will bounce, ...
user189508
41
votes
6
answers
8k
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How does rotational "artificial gravity" differ from normal gravity?
I am not a physicist, just a curious mind. I was reading a novel by Iain Banks where it was mentioned, that shifting from artificial rotational "gravity" (in space, on a rotating space craft) to real ...
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37
votes
5
answers
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Why can't we feel the Earth turning?
The Earth turns with a very high velocity, around its own axis and around the Sun.
So why can't we feel that it's turning, but we can still feel earthquake.
- 519
29
votes
8
answers
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Why is Microgravity called "Microgravity"?
I find the term "microgravity" to be misleading, how was it coined?
NASA provide this definition:
Microgravity is the condition in which people or objects appear to be
weightless. The ...
- 457
28
votes
4
answers
6k
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Can a submerged object in a free falling fluid sink faster than falling?
I've been wondering about how sunken objects would behave if you could instantaneously flip their container with water. Like if you had a bucket filled with normal tap water and you dropped a ball in ...
- 399
28
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4
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Are planets actually moving in elliptical orbits around the Sun or do they move in circular orbits around their center of mass?
In every derivation of Kepler's Laws that I have seen, we assume that the sun is stationary. However, in other places I have read that celestial bodies move about their barycentre (center of mass).
So ...
27
votes
8
answers
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Why doesn't the Earth accelerate towards us?
According to Newton's third law of motion that states that every action has an equal and opposite reaction.
So, if the Earth exerts a gravitational pull on us (people) then even we should exert a ...
- 1,033
26
votes
6
answers
10k
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Why do we assume weight acts through the center of mass?
The weight of a body acts through the center of mass of the body. If every particle of the body is attracted by earth, then why do we assume that the weight acts through the center of mass? I know ...
- 451
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7
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Gravity on the International Space Station
We created a table in my physics class which contained the strength of gravity on different planet and objects in space. At altitude 0 (Earth), the gravitational strength is 100%. On the Moon at ...
- 363
25
votes
6
answers
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Is the force of gravity always directed towards the center of mass?
This is a pretty basic question, but I haven't had to think about orbital mechanics since high school. So just to check - suppose a [classical] system of two massive objects in a vacuum.
If the ...
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23
votes
5
answers
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Does a person inside a falling bus fall to the front of it?
So I was watching Final Destination 5 and something caught my attention. There's a part where a bridge collapses and everything falls apart, so there's this bus that has a person inside (unaware of ...
- 333
18
votes
7
answers
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Why doesn't the Earth's acceleration towards the Moon accumulate to create noticeable motion of the earth, towards the moon
I get that Earth's mass is very large, so its acceleration is very tiny. But wouldn't the acceleration accumulate over a period of time and become noticeable?
- 408
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If centrifugal forces are fictitious, then isn't gravitational force also fictitious?
When the earth revolves around the sun, the sun attracts the earth by a gravitational force $F_{se}$ (centripetal force), and the earth attracts the sun by a gravitational force $F_{es}$ (centrifugal ...
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