# inertial

1. ### Inertial Frame and Non Inertial Frame

Hello everyone I have 2 Questions for you. Thank you for your all answer. 1) Can we say that a nonrotating frame with its origin at the center of the earth (earth-centered frame) is inertial, even though the earth is accelerating and rotating? 2) Can we say that a nonrotating frame with its...
2. ### When Does an Observer Become an Inertial Observer?

Inertial observers can legitimately use the famous time-dilation result of special relativity to determine simultaneity at a distance. Observers who are currently accelerating can't. To be an inertial observer during some period of your life, do you have to be a PERPETUALLY inertial observer...
3. ### Inertial "moment" of a solid given an inertia tensor

Hi all, I am programming some software computing inertial forces of some moving structure. So far, the structure have been represented as a cloud of mass points. For each mass point, inertial forces are computed using some formulas like in this article...
4. ### Inertial Equivalence

I have seen a number of posts indicating that while it seems impossible to identify any difference between the inertia from acceleration and the inertia from gravity, there has been no theoretical reason discovered why they must be the same I have been thinking about this... As an object is...
5. ### Simultaneous in all inertial frames

The question I have says that a comet is travelling at speed v and people are having a party to celebrate the crashing of the comet. If the comet has to travel 8x10^11 m then how long do they need to have a party for, for the party to be simultaneous with the crash in all inertial frames? My...
6. ### Inertial frames of a falling stick

"In an inertial frame of reference 1 a stick AB of Length L parallel to the x-axis falls down vertically under gravity, reaching the ground at time t=t*. In a different inertial frame of reference 2, which is moving with respect to reference frame 1 in the x direction with velocity v2,1, the...
7. ### New definition of a non inertial frame of reference.

The present definitions of non inertial frame of reference are vague. Some would define it to mean that a non inertial reference frame is one which does not obey newtons first law. But we can define a non inertial frame of reference in this way. "A non inertial reference frame would be one...
8. ### Inertial force depends on mass in general relativity as well as classical mechanics.

PMB can you explain your analysis as to why you said that inertial force does not depend on mass. Einstein mentions that spacetime warps around massive objects and the more heavy an object is the more spacetime is warped meaning more gravity. Now even though gravity depends on mass in general...
9. ### Force acting in a non inertial frame of reference.

A non-inertial frame of reference does not have a constant velocity. It is accelerating. Lets take an example of a non inertial frame of reference or an accelerating frame of reference. Lets say the frame is traveling in a straight line, but speeding up or slowing down. Lets say a ball is...
10. ### What precisely are "inertial" forces?

This concept seems to be hanging me. It's used in a lot of D'Alembert problems and even on various texts on the web. The wiki page on "D'Alembert's principle" points to a page called "fictitious forces". https://en.wikipedia.org/wiki/Fictitious_force Except the wiki page on this starts...
11. ### Inertial moment variation

Hi, I would like to ask a question, if I may: if I have a body with a calculated Inertial moment and angualr momentum at time t0, that in a space of time delta t changes, there's a variation in its kinetic energy, right? How can I calculate the released temperature in that elapsed time? Is...
12. ### constant Jacobian transformation of an inertial frame

Suppose we do a constant Jacobian transformation (NOT Lorentz) of an inertial frame. This defines a non-inertial field with a constant metric in which the acceleration vector is NON-ZERO. But this directly contradicts the geodesic - metric equation. According to this equation, the...
13. ### Inertial moment of pendulum watch

Hello guys, how are you? Well, here is my doubt: "The pendulum of a watch is formed by a thin rod of 207g and 20cm lenght and by a disc of 398g and 11cm of diameter. When the pendulum rotates around the extremity of the rod, with the plane of the disc perpendicular to the rotate axis, it's...
14. ### Fictious forces: brain teaser

Ok so I read that the laws of classical mechanics hold in every inertial reference frame, that is, a system of coordinates that has constant velocity and direction. This is named the principle of relativity (not Einstein's). In order to understand this, I tried to think of a counter example...
15. ### Relativity- inertial frames

Suppose the space time co-ordinates of two events in inertial frame S are as follows: Event 1: x1=x0, t1=x0/c y1=z1=0 Event 2: x2=2x0, t2= x0/2c y2=z2=0 Show that there exists an inertial frame s' in which these events occur at the same time (i.e t1'=t2') and find the value of time for...