Frame of reference Definition and 203 Threads

I know the Galileo invariance don't allow us to take rotational or accelerating frame reference but an shrinking frame reference wouldn't be neither of this. so would be allowed to take an shrinking frame reference?

Suppose I am observing a object in a noninertial frame from a noninertial frame , then what will happen to the forces acting on a object with respect to both the frames, frame of reference (FOR) moving uniform with inertial FOR are themselves inertial frame , does it follow the same with a FOR...

Definitions: Astronaut is A Person on Earth is B A travels to a star far away at near light speed, A would see B's time dilate. B would also see A's time dilate Twin paradox revived: What would happen if A returns to B at a very slow speed? Then both frames of reference would see each others'...

I'm getting quite stuck on this problem here. Galileo said that Xb = Xa - V*Ta. (This follows from dv = dx/t --> Xa - Xb = t*dv --> the above formula) Thus, it is concluded Xa = Xb + V*Ta, but why? In my thought experiment the objects are moving relative to each other, thus if A is moving away...

Newtons first law of motion depends on frame of reference So what are some examples , which shows that in this frame of reference F = 0, but a is not equal to zero or vice versa.

If two particles are moving apart, how is it determined if they are moving through space or if the motion is due to the expansion of space-time? Especially if there was no other frame of reference.

is there any thing which is at rest with every frame of reference. what if an object experiences this situation.

why can't speed of light be relative to it's source?

According to special relativity, KE= ([PLAIN]https://upload.wikimedia.org/math/3/3/4/334de1ea38b615839e4ee6b65ee1b103.png-1)(mv^2)/2. Since the velocity measured is dependent on a person's frame of reference, then does that mean energy too is dependent on frame of reference? For example, if an...

If moving inside the event horizon of a super-massive black hole and theoretically surviving we could see the universe pass by at millions of years per second relative to someone on earth, where could we go where time passes at a much faster rate than someone on earth? For example where 2...

Homework Statement You use a string to suspend a cork ball with a mass of 22.0g from the ceiling of a moving speedboat. The ball and string hang at 32.5 degrees from the vertical. Calculate the acceleration of the speedboat.Homework EquationsThe Attempt at a Solution I was able to calculate...

And a cartesian axis system in physics? I thought about that and my answer is that a cartesian axis system is the same as a inertial frame of reference, is that true?

Hello, I wish to know what is the relationship between a frame of reference and time. Specifically,without a frame of reference, what would be a hypothetical state of time. Professor Witten predicts that an ultimate physical theory will dissolve space-time as we know it. I would like to discuss...

If I am sitting, not moving, my velocity can be zero along with my acceleration but in truth the Earth is moving along with the solar system and so on but i want to know theoretically if a massless object in space can have zero velocity and zero acceleration, in essence what i am askimg is can...

What kind of frame of reference do I have to choose when I'm studiyng lens and mirrors? As far as I know you consider positive the direction where the rays are real and negative the one where the rays are virtual, is that always true? Why can't we study a problem of optics choosing a frame of...

Whenever we define torque from a frame of reference, is it necessary for the frame to be inertial? Please explain because I am unclear on this.

Hello, My understanding is that a a frame of reference is a theoretical framework that is used to describe the motion of an object allowing for measurements of position, distance and time. A frame of reference always implicitly includes a coordinate system (cartesian, spherical, cylindrical...

Is the inertial frame of reference the same thing as space time?

I'm currently doing a student project at uni and I'm trying to design magnetorquers for cubesats.Before I make the prototype I need a simulation of what will happen.The problem is that for my calculations,I need to change the frame of reference of the geomagnetic field.So basically I need to go...

So, a friend asked me this question in school and I've come up with an answer, I'm just not sure that it is right. Say you have a charged particle moving perpendicular to a magnetic field. There will be a force acting on it given by F=qvB. Now suppose your'e moving along at the same velocity as...

The reason we can choose a frame of reference arbitrarily is that a physical system is not dependent on an absolute position, orientation or time. According to Noether's Theorem, the invariance of a system under a change of position is equivalent to the momentum conservation law. In the same...

In an inertial frame of reference let numerous standard rockets that load synchronized standard clocks place on all the space lattice. Simultaneously the rockets start to move with same intrinsic acceleration to the same direction. In other words there exists a common instantaneous inertial...

If light travels in a straight line , why can't we use it as absolute frame of reference? This thought experiment is done in the absence of external forces and gravity. One person standing inside a box ,sends a photon parallel to the bottom of the box from one end to another end , whether...

Hi, I have a reference device that outputs euler angles, which are angles that relate the sensor body frame to the north east down frame. These angles are called pitch roll and yaw. The sensor is an accelerometer. I know how to get the rotation matrix that will put accelerations from the...

Hello all, was it ever a point of discussion in cosmology, quantum-theory, mechanics, etc. that there is a fundamental difference in describing a physical process in a 2n-grade (4th, 6th, 8th-grade) frame of reference in comparison to a 2n-1-grade (3rd, 5th, 7th-grade) frame ? Thanks in...

Homework Statement A car is moving toward north with a speed of 35 km/h. A truck travels toward west with a speed of 42 km/h. Which is the speed of the caravan according to the car's driver? Homework EquationsThe Attempt at a Solution The solution given by the book is 15 m/s with direction...

Hi, This might sound very basic and but i am just starting to learn physics. I an lecture by prof. walter lewin, he descibes the hunter and monkey scenario. The monkey jumps from the tree as soon as the hunter aims and shoot his gun. the bullet hits the monkey anyway. In calculating the time it...

Hello, Please: • Assume a universe void of all matter • Visualize 2 parallel paths, 10 meters apart. Let’s call them x and x' • Vessel X is moving along x and vessel X' is moving along x' • Vessel X has a mass of 1 metric ton and vessel X’ has a mass of 2 metric tons • At t0 the...

Dear PF Forum, Sorry if I ask again, because I want a detailed information. Does the universe has a frame of reference? Two twins. A stays, B "travels". (Travel here is confusing, B will say I stay and A travels) and B "turns around" and come back. B ages more slowly then A. Q1: Why? A1...

Hi Friends , I had a discussion with a funny person last night. He said the following argument : Suppose there are 21 objects including the one object under consideration. Each of the 21 objects move with a velocity. Since there are 21 objects, for the object we are considering has 21...

Dear PF Forum, Again the same question about preferred frame of reference. I have read several threads in Physics forum, but I think this question belong to cosmology. And I have searched in Google and in PF forum threads, so, I'll ask some confirmation here. 1. Does the universe have a...

When I was surfing on a group in Facebook, I found two concepts very difficult to understand by reading the discussions in comments. Those concepts are inertial and non inertial frame of reference. Please make me understand these two concepts in simple words. Please don't suggest links as I...

Homework Statement A wheel of a bicycle weighs 1 kg, all of which is at the rim. The diameter of the wheel is 0.7 m. If the bicycle is ridden at the speed of 3.5 m s–1, then in the frame of reference of the rider: i) Calculate the angular speed ω of the wheel. ii) Calculate the momentum of...

Homework Statement Our teacher said we can NEVER do an F=ma problem from an accelerating, or noninertial frame. (He said there are ways to do it, but we can not do it in his class), and I'm confused becuase often times he makes the "system" or makes a "free-body diagram" around an accelerating...

Hi, I am new here, but there is a question that really bugs me :-(. In Lorentz force why was the velocity defined as relative to the observer and not relative to thesystem generating the magnetic field. By defining it relativ eto the system relativity is not needed to explain how an observer...

I'm studying special relativity for the second time and there's something I think I didn't get since I studied classical mechanics: the idea of a frame of reference. I think the underlying idea is that of a point of view, so that we want to study some phenomenon, but we have to observe it so...

So I understand that in classical physics, movement only makes sense with reference to another body. So my car moves relative to the surface of the road, for example. But it seems that with acceleration, things appear to be more complicated than that. Let's say we have two objects in space...

You are standing on one. The two planets were closing in on a speed of 1x. You just accelerated one of the 2 planets towards the other with a super powerful rocket engine, and then sat on one of them. Now they are closing in on each other at speed 10x. The universe is otherwhise empty. The...

We know that when a rigid frame, say a rocket undergoes constant proper acceleration, its worldline is hyperbolic. The equation is given by: x^2 - c^2t^2 = \left( \frac{c^2}{a_0} \right)^2 Suppose P is such a worldline and worldine can also be written as: I understand how these are...

If you have a car and a pendulum is hanged inside it, and if you watch from outside the car,and if the car has some acceleration, then you see the bob moving in opposite direction of motion of car. For a person standing outside, he knows that the car has some acceleration. What causes the bob...

Alright so I'm still trying to get a hang of the theories of relativity, and this thing has really been bugging me. All forms of motion (and sometimes even physical observations) are defined for a particular local frame of reference. But is there any "stationary" frame of reference in the...

Hello, I was wondering about a question and how it would be reconciled within Newton's laws of motion. Take a case where two boxes are stacked on top of each other, and the bottom box rests on a frictionless surface. Now, imagine a rope is attached to the top box, and tension is applied to...

My apologies for the numerous times this has probably been posted, but I wasn't able to find a great answer through the search tool alone. Please correct me on anything I state incorrectly, and direct me to the answer.. My question is, if the speed of light is 299,792,458 m/s, its speed is...

My friend posed a question to me that I was unable to succinctly answer (or answer at all for that matter). So I thought I'd make an account and ask people who know more about this than I do. Ok. So let's assume that Person A starts at Position 1. Person B is at position 2, which is 1 light...

I already have the solutions emailed to me from a D H Lawden textbook. I have trouble understanding the solution as the solution is not formatted properly, and the answer seems to be a little too advanced for me. I hope that some one can help me understand the problem. 1. Homework Statement...

I apologize if this has been discussed before. I am no physicist, I am just trying to see if I am understanding special relativity correctly. Please be advised I am dumb, so be gentle. If a spaceship (sorry for the cliché, but it's a little bit cumbersome to keep using the phrase "inertial...

If a metallic ball is place inside a giant hollow top, and the top starts to rotate. Along with the top, the metallic ball will also start to rotate. Thus my question is the ball motion is under inertial frame of reference or non-inertial ?

If a metallic ball is place under a giant hollow top, and the top starts to rotate. Along with the top, the metallic ball will also start to rotate. Thus my question is the ball motion is under inertial frame of reference or non-inertial ?

How Earth is considered to inertial frame of reference?

Does the existence of the "Axis of Evil" observed by WMAP and Planck mean that there is a special frame of reference in the universe?