# Linked Questions

3answers
6k views

### What is an inertial frame? [duplicate]

Throughout my life I've been told that an inertial frame is one that is not accelerating and I was satisfied with that. Well up to this day, until I asked: accelerating with respect to what ? Now this ...
1answer
636 views

### How can you tell if a given reference frame is inertial? [duplicate]

An inertial reference frame is one in which a particle has constant velocity if and only if has a zero net force acting on it. How can one determine if a given reference frame is inertial? For ...
4answers
337 views

### Is rotation absolute? [duplicate]

I was reading an article that rotation instead of linear motion is absolute. Can anyone explain why? Shouldn't an observer (A) moving in a circle around a point in an object that rotates (with respect ...
1answer
189 views

### Non-inertial system [duplicate]

Supposing I am in a non-inertial system and I don't know what forces are acting. How can I test EXPERIMENTALLY and in practice to be in a non inertial system? If I am in a system and I don't know how ...
2answers
148 views

### Newtonian physics [duplicate]

According to the book I am referring while working with non inertial frame of reference we have to apply a pseudo force equal to mass x acceleration in the opposite direction of the acceleration of ...
0answers
38 views

### Grasping (Inertial) Frames of Reference [duplicate]

I am new to studying Special Relativity and have some trouble truly understanding what the phrase (Frame of Reference) tries to imply. So I understand that an inertial frame of reference, for example,...
0answers
30 views

### How can an observer know that he is in an accelerating reference frame? [duplicate]

Question: Could a mechanical experiment be performed in a given reference frame which would reveal the information about the acceleration of that frame relative to an inertial one? My Guess: I have ...
15answers
16k views

### Why do we say that the Earth moves around the Sun?

In history we are taught that the Catholic Church was wrong, because the Sun does not move around the Earth, instead the Earth moves around the Sun. But then in physics we learn that movement is ...
7answers
6k views

### Why does rotation simulate gravity if motion is relative?

In Einstein's theory of relativity, if motion is truly relative, then why would somebody in a rotating space station experience (artificial) gravity? I mean, I get why they experience gravity IF the ...
7answers
7k views

### How does a spinning object “know” that it is spinning?

I am constructing a thought experiment about a spinning object that is floating in intergalactic space. I assume that this object is about the size of a planet so that it will have enough gravity so ...
10answers
5k views

### What is the Earth truly rotating about/revolving around?

Earth rotates on its axis and revolves around the sun, the sun revolves around the galaxy, the galaxy is also moving. So Earth's net rotation as observed from a fixed inertial frame consists of all ...
3answers
987 views

### Is it possible to speak about changes in a physical constant which is not dimensionless?

Every so often, one sees on this site* or in the news† or in journal articles‡ a statement of the form "we have measured a change in such-and-such fundamental constant" (or, perhaps more commonly, "we ...
7answers
18k views

### Is there any true inertial reference frame in the universe?

Is there any true inertial reference frame in the universe? Newton's first law states that an object at rest remains at rest, and an object performing uniform motion performs uniform motion, until ...
7answers
4k views

### What does the statement “the laws of physics are invariant” mean?

In the first paragraph of Wikipedia's article on special relativity, it states one of the assumptions of special relativity is the laws of physics are invariant (i.e., identical) in all inertial ...
5answers
4k views

### How does one determine an inertial frame?

How does one determine whether one is in an inertial frame? An inertial frame is one on which a particle with no force on it travels in a straight line. But how does one determine that no forces are ...

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