Reference frames Definition and 228 Threads

My understanding is that as I move, from my FoR all objects and space itself (according to Einstein) contract along the direction of my movement. This length contraction occurs for all space and objects in front of me for an infinite distance. Furthermore, relative motion is relative, and the...

my question comes from the portion of the derivation regarding evaluating the rate of change of the principle axis vectors. this begins by supposing a vector, Q, is rotating about axis n by δθ. Specifically, my question is how from step 4 to step 5 the approximation becomes an equality. Q'...

My question regards how the approximation becomes an equality.

Homework Statement In the laboratory frame, event 1 occurs at x = 0 light-years, t = 0 years. Event 2 occurs at x = 6 light-years, t = 10 years. In all rocket frames, event 1 also occurs at the position 0 light-years and the time 0 years. The y- and z- coordinates of both events are zero in...

Homework Statement K mesons (“kaons”) are unstable particles composed of a quark and an antiquark. They can be produced copiously in energetic collisions between stable particles at accelerator laboratories. Soon after they are produced, kaons decay to lighter particles. One type of kaon...

Homework Statement Suppose you have a spaceship and in the spaceship is a block on an frictionless incline. Initially, the spaceship is at rest on the Earth's surface. The astronaut in the spaceship observes the block sliding down the incline with acceleration Mgsinθ . Now consider that the...

What is an inertial reference frame?How are positions,velocities and accelerations changed when switching between different inertial reference frames? r=rx i + ry j + rz k Inertial reference frame:It is a frame of reference where Newton's laws of motion is valid.No fictitious...

I know total energy is conserved, but does this mean that different frames agree on the total energy of a particle? I'm assuming they don't agree on energy, because if I measured the total energy of a particle moving relative to me (which would equal the rest energy plus its kinetic energy)...

can inertial reference frame ever have "lenght contractions" in 3d or in rest? hi! thank you for all answers in this topic in previous threatin same topic. i open this new thread in same topic but here i try to keep the issue here very short and readable , with no speculation and concentrating...

Homework Statement Particle track detectors are used to measure the speed of particles if the lifetime of the particle is known. Particle X has a lifetime of 256.2 ps. These particles are created in an experiment inside the detector by a given reaction. The particles leave 21.8 cm long tracks...

Homework Statement I have this assignment on where I have to make up a scenario and solve for the question. The question is that there is a baby that is being thrown out of building into a moving car, (to keep the baby out of harms way). How fast would the car have to traveling to catch...

Homework Statement There are two particles with rest masses m1 and m2. In the S frame they have velocities u1 and u2. Consider another frame, which we usually denote as the S0 frame, which has a velocity v in the S frame in the direction of increasing x (i.e., it is going to the right in the...

I've read all sorts of descriptions in textbooks and online, but I don't get the purpose of reference frames. Why can't you just put everything on the same set of coordinate planes? I don't see what difference it makes. There was an example with a car traveling alongside another car, and that to...

Homework Statement You are traveling in a car going at a constant speed of 100 km/hr down a long, straight highway. You pass another car going in the same direction which is traveling at a constant speed of 80 km/hr. As measured from your car’s reference frame this other car is traveling at...

I'm a bit unsure about the last couple of bits of this question, and I'm hoping someone might be able to help. Homework Statement a) Let a reference frame with origin O & Cartesian axes (x, y, z) be fixed relative to the surface of the rotating Earth at co-latitude θ (i.e. 0≤θ≤∏, where θ...

Hi to all, I am a new one to this physics forum and i have a doubt regarding Inertial Reference frames. In an article of IRF, it is given as "There is no absolute inertial reference frame, meaning that there is no state of velocity which is special in the universe." Can anybody please...

Homework Statement A space traveler takes off from Earth and moves at speed 0.99c toward star Vega, which is 26.00 ly distant. How much time will have elapsed by Earth clocks when the traveler reaches Vega? 2. The attempt at a solution I looked at the problem solution, which...

Basically: I jump forwards, exerting an amount of energy enough to push me forward with some velocity. But in my reference frame, I exert the same force, except the entire universe moves backwards with that same velocity, where did that energy come from? I sort of know this has to do with...

Ok I'm really trying to understand inertial and non-inertial reference frames, my understanding is as follows: A rest observer on the earth, the observer will be stationary relative to the earth.. Now as I understand it an inertial reference frame is one of which 2 coordinate systems are both...

My question is not homework. I feel ashamed of having this doubts but I'm really stuck on this. The problem is I have a reference frame xyz and here I define the COM \vec x{_{cm}} of the system. Now I move the COM reference frame x'y'z': \vec{x'}=\vec{x}-\vec x{_{cm}} In this reference frame I...

Homework Statement The Millenia is catching up to the Galaxa at a rate of 0.55c when the captian of the Millenia decides its time to fire a missle. He uses a laser range finder to determine the distance to Galaxa and then he fires a missle that is moving at a speed of 0.45c. What...

Homework Statement The distance from Planet X to a nearby star is 12 Light-Years (a light year is the distance light travels in 1 year as measured in the rest frame of Planet X). (A) How fast must a spaceship travel from Planet X to the star in order to reach the star in 7 years...

Homework Statement A 20g ball of clay is shot to the right at 12m/s toward a 40g ball of clay at rest. The two balls of clay collide and stick together. Call this reference frame S. Homework Equations What is the velocity of a reference frame S' in which the total momentum is zero...

Hello, I am having difficulty understanding the concept of Newton's first law only applying in an inertial reference frame, or a frame that is at constant velocity, however, apparently the 1st law no longer applies if the reference frame is accelerating. Can anyone give me some sort of concrete...

Homework Statement I a little lost on how to use the relativistic velocity addition formula to determine the increase in speed "v" over a short time interval in the Earths frame of reference, for a rocket having left Earth at rest and traveling through space accelerating at constant acc. of...

The initial presentation of Newton’s Laws of Motion (NLM) to students often proceeds as follow: 1. The 3 laws are presented, 2. The caveat that the laws are only valid in Inertial Reference Frames (IRFs) is (sheepishly) mentioned, 3. An attempt is made to define an IRF, and 4. Some examples...

As I understand in SR light is always c in it's local reference frame regardless of a present gravitational field. Light would appear to be traveling slightly less than c in a gravitational field otherwise known as the Sharpio Delay in all non-local reference frames. Now, light must be traveling...

Homework Statement Do objects same kinetic energy in all inertial reference frames? For objects interacting, is energy conserved in all inertial reference frames? Homework Equations None The Attempt at a Solution I think the answers are No for the first one, and Yes for the...

I am re-posting this question here in a new thread as Humber mistakenly posted it in a two year old thread.

Is it possible for a particle to exist according to one reference frame and simultaneously not exist according to another? If energy is relative, can a collision between two particles have enough energy to produce new particles according to its own reference frame but not have said amount of...

i came over the terms 'inertial' and 'non-inertial' frames during the study of rotational motion...pls clarify the difference...! plus can anyone give me a link from where i can practice numericals of angular momentum, moment of inertia, torque..

The speed of light, the term "light year", and reference frames. Hi everyone. This is my first post, and I post out of desperation. A friend of mine and I were casually discussing Time Dilation, interstellar travel, etc. when we came to a point we fundamentally disagreed upon. Neither of us...

The first law of motion says that it takes force to accelerate something. The second law of motion says that F=ma. So now my teacher says that the first law is for inertial reference frames, while the second is for non-inertial reference frames. This really annoys me because I don't...

If one wants to calculate the elapsed time from the perspective of an object A moving at velocity, v, for time, t, relative to a stationary object B, all you have to do is calculate: \int_{t_o}^{t_f}\frac{t}{\gamma} Of course, \gamma has no dependence on t because v is constant, so we get...

a frame of reference is moving with a constant velocity with respect to a inertial frame of reference,then moving frame will be inertial itself?

Hello there I have 2 questions: 1. Can one change the coordinate system of torque vectors through a homogeneous transformation matrix with both rotation and displacement? 2. What's the procedure to add two torque vectors about different axes? Thanks in advance, João

An inertial frame is one which is not accelerating. i.e if I'm sitting in an accelerating bus or plane I'm not an inertial observer however if I am in a bus or train traveling at a constant velocity i.e zero acceleration then I am an inertial observer. One thing Id like to ask here is that...

Homework Statement Challenge: a rather eccentric group of astronomy students wanted to celebrate the impact of the Shoemaker-Levy comet on Jupiter by holding a party of sufficiently long duration that their celebrations were simultaneous with the impact of the comet in all inertial reference...

Homework Statement [PLAIN]http://online.physics.uiuc.edu/cgi/courses/shell/common/showme.pl?courses/phys211/oldexams/exam2/sp10/fig3.gif A 4.0 kg circular disk slides in the x-direction on a frictionless horizontal surface with a speed of 5.0 m/s. It collides with an identical disk that is...

Hey, this is my first post. I am a biology major so I know pretty much nothing about physics, yet sometimes it interests me way more than chromosomes do. So, given that I know nothing about physics, this is probably going to sound like a stupid question. But I've always wondered how it is...

This website has an animation that shows the difference between sidereal reference frames and synodic. http://www.sumanasinc.com/webcontent/animations/content/sidereal.html The motion of the moon is circular about the earth, yet apparently the moon has an apogee length that is 50,000 km...

Homework Statement A 110-m-wide river flows due east at a uniform speed of 3.3 m/s. A boat with a speed of 8.6 m/s relative to the water leaves the south bank pointed in a direction 37 degrees west of north. What is the (a) magnitude and (b) direction of the boat's velocity relative to the...

Let’ say; “A” can see and measure a stone falls to the Earth let’s say 10 meter per 1 Earth-second. “B” lives at Mercury and can see the same thing. But “B” would do not see the exactly the same, because seen from “B’s” viewpoint time / distance is not the same as for “A”. Let us say...

in at 0:47:00 Susskind begins discussing accelerated reference frames and notes that they relate to hyperbolas rather than parabolas. I understand the concept and need for the proper acceleration to be asymptotic at C. Susskind seems to infer that an observer in the accelerated frame will...

Homework Statement Let's say that there is a bicycle traveling forward and we only see it from behind. As it rolls to turn, it induces some accelerations. If we were to measure those accelerations on the bicycle frame itself, we would see a Lateral Acceleration (lets call it Aym) and and a...

I found this article: http://www.csa.com/discoveryguides/gravity/overview.php" The article says gravity moves at the speed of light. But does gravity do so in any reference frame, like light does? Thanks, Jake

Quick question: Is Planck time the same in all reference frames? Is it different at, say, half the speed of light than at a relatively stationary point? What about in a severe gravitational field, like a black hole?

Consider two point charges in space: one positive(+Q) and other negative(-Q), lying on the y-axis and separated by distance 'r'. In frame A, both charges are at rest so, only attractive electrostatic force (F_elec) acts on both the charges which is defined by coulombs formula. In another frame...

What is a non-inertial reference frame? how is it defined?

Dear all, I'm trying to understand better why gravity makes impossible to physically define an inertial reference frame. Firstly, we must have an operational procedure that allows us to physically define an inertial reference frame. Secondly, we must show that gravity makes this procedure fail...