Frames of reference Definition and 111 Threads

Hi everyone, this is my first post in the site. I post this thread below 'Mechanical Engineering' topic because i see most drone questions is posted under this subject but question can be more suitable to other subject so please let me know. In quadcopter dynamic equations of Newton-Euler...

A doubt has arisen for me about the principle of relativity, and being such a fundamental subject I think it only fair to try and clarify it. The following line of reasoning was presented to me in a lecture, but is it really correct? It seems very unstable to me. Take two frames of reference...

I am having a discussion with a couple of very obtuse individuals on another forum who think they know celestial mechanics, but do not. These two have long promoted themselves to be something they are not, and since I am rather new on the forum they are unwilling to even listen (or heaven...

The electric field inside a charged spherical shell moving inertially is, per Gauss's law, zero. If the spherical shell is accelerated, the field inside is not zero anymore, but it gains a non-null component along the direction of the acceleration, as mentioned, for example, in this paper. The...

Just want to clarify some concepts. There seems to be difference between reference frame and coordinate system. See https://en.wikipedia.org/wiki/Frame_of_reference#Definition . A reference frame is something has physical meaning and is related to physical laws, whereas coordinate system...

The correct option is given as (d) I think I am able to visualize the problem but not able to put it in the equations shared above. If the the two frames are moving away from the particle at ##4 m/s^2## in opposite directions we get the acceleration between the frames as ##8 m/s^2##...

Good morning! I know this may sound a little odd, because there is a theorem regarding it, but i have this question. Basically, a CFD analysis gives me the value of the forces and the moments, as a function of fuselage's orientation, in a particular frame of reference. How can i calculate the...

pls help me

I am trying to figure out what are inertial observer and inertial frames of reference. The law of inertia holds for inertial observers. Inertial observers are objects with zero net force acting on them, and move with constant velocity. Suppose we fix a set of coordinate axis in space, relative...

This problem is conventionally solved using the Earth frame of reference. We require that the hyperbolic excess velocity w.r.t. the Earth has the same magnitude as the speed of the Earth around the sun, so that we zero the velocity in the heliocentric frame. Energy conservation per unit mass in...

Hello Is it even possible to have an answer for D given condition #4 ? i need help in just for question D, and not everything else . Thanks :] The Attempt at a Solution Because Either S or S' Could be accelerating, and depending on which one and how much is accelerating, there will be different...

Hi everyone. Please be gentle with me, I am not a physicist! I am a layperson with an interest in learning more, and I’m reading a book called ‘How to Teach Relativity to Your Dog’ by Chad Orzel. It’s supposed to be physics for dummies, but it’s clearly not dumbed down enough for me because...

Homework Statement 3. (a) If an object's acceleration is zero in one inertial reference frame then is its acceleration zero in all other inertial reference frames? (b) If an object's velocity is zero in one inertial reference frame then is its velocity zero in all other inertial reference...

Can we truly have a rest frame or should it be a close to rest frame? Even if I'm stationary and sitting on my porch and the observer in the car passing is moving, I'm still not at 0 velocity. The Earth is moving at 67,000 mph and the galaxy is moving at 250,000 mph. I'm never in a single...

I am reading through a textbook on AP Physics, and I came across a few references to non-inertial frames of reference. It doesn't clearly say what a non-inertial frame of reference is. Based on the examples it gives, I assume that it is a frame of reference where the observer is experiencing...

Homework Statement Imagine that you are flying on an airliner on a long flight to Europe, at a constant speed of 300 m/s. a) You throw a ball towards the back of the plane at 20 m/s. You then shine a beam of light towards the back of the plane. How will these two things—the ball and the...

Can anyone briefly explain the difference between covariance and invariance in terms of special relativity? My understanding is that an invariant quantity is a value which does not change regardless of frame of reference it is being measured in. Covariance is a value which when measured in...

Suppose we have a rotating frictionless disk and there is a rotating observer on the center of it. Furthermore, suppose a very small ball on the disk's edge. Now we clearly know that the ball is not moving but the rotating observer sees the ball following a circular path with an angular velocity...

Hi, Could someone please have a look at my solution and let me know if I did it correctly. Thank you! 1. Homework Statement A pilot is flying from City A to City B which is 300 km [NW]. If the plane will encounter a constant wind of 80 km/h from the north and the schedule insists that he...

Suppose I'm an observer out in space and 30 km from me there's another observer, who is static with respect to me. Let's say my name is A and the other is B. We're both far far away from all the cosmical objects that might have a gravitational influence on us. We both notice a spaceship flying...

I study electromagnetism and I got to the chapter about special relativity, in this chapter my professor (since we are not using the electromagnetic tensor in this course) used a specific case to show that the electric field parallel to the velocity of a frame of reference stay the same in both...

So, I have been thinking about TRAPPIST-1 and how far away that system is from us. It is 40ly away from Earth, according to our frame of reference. This is often put in a way that makes one think that even at speeds close to that of light, it will take almost 40 years to get there. The muons in...

Hi people, I have a question about the frame of references. Let's have an example: First case: Jill on rocket and Jack stationary on Earth. Jill moves relatives to Jack 0.6c (1.8*10^8m/s). The distance is 18*10^8m. At the zero time Jack and Jill synchronize their clocks. Then Jill starts to...

kuruman submitted a new PF Insights post Frames of Reference: Linear Acceleration View Continue reading the Original PF Insights Post.

Ok I have a really basic question. Say you and I are floating in space and there is a single electron in front of us stationary to our frame of reference. Now I start hopping up and down. I see the electron accelerate up and down from my hopping frame of reference. I see a EM wave be...

What determines whether a frame of reference can be considered stationary? I assume it is not allowed that the Earth be considered stationary and the universe is moving around it for example, as I would have thought that would lead to observation of faster than light movement. In...

Homework Statement The Observer (me) is at Inertial Frame of Reference: 1) I am sitting at a car moving east v=30 km/h relative to earth A bird flying east v = 10 km/h relative to earth What is the speed of bird for me? 2) I am sitting at a car moving east v=30 km/h relative to earth A bird...

kuruman submitted a new PF Insights post Frames of Reference: A Skateboarder's View Continue reading the Original PF Insights Post.

With a velocity dependent equation such as de Broglie's λ=h/mv There's just so many questions, where do I start... In your frame of reference, an electron might be standing still but from an outside frame it could be moving at 0.1c does that mean you'd see different wavelengths? What about when...

Homework Statement A clock moving at v = (3/5)c reads 12:00 as it passes us in our frame of reference, how far away will it be (in light hours) when it reads 1:00. Homework Equations I denote a prime to mean the reference frame of the clock at rest. I use regular lettering to denote 'our'...

It's said that, speed of light is same in every frame is reference. Consider an ideal situation, if I'm also moving at the speed of light, will I feel light to be at rest or still at the speed of light itself according to my frame of reference?

Why is speed of light constant in all frames of reference. I don't understand.

Homework Statement Why do objects that have no external net force acting on them accelerate? Ex. If a ball is on an accelerating train, it will accelerate opposite the direction of the train's acceleration, assuming there is nothing blocking its path of motion and it is not strapped down. My...

Homework Statement You are in a car accelerating forwards. There is a baseball at your feet. Draw two FBDs showing the the ball's motion from the frame of reference of the car and the frame of reference of the sidewalk. Which frame of reference is non-inertial? In which frame do you observe the...

is space an inertial or non inertial frame of reference?

OK, I'm sure I'm just not thinking about this the right way, so please point out my simple mistake. Imagine a charged particle and 2 observers. Observer S is stationary relative to the charged particle, so sees no magnetic field from it. Observer A moves back and forth in front of the...

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, I have been studying lorentz force . The book says force experienced by a charge in magnetic field is But velocity is a relative concept . In one frame of reference(inertial frame) I might observe the charge moving with some velocity and in the 2nd frame(inertial too) I might observe the...

While trying to understand how each frame of reference predict that the other is slower, I discovered what seems to be something unsymmetric. It looks as if it is possible to determine that a frame of reference is not one truly standing still. But that's impossible right? I'm really interested...

An accelerating charge radiates light. But in its own frame of reference it is stationary. So it does not emit light. How is this explained? Extreme Example: A charge inside an elevator is falling in a gravitational field. The elevator is lined with a light sensitive sensor that triggers a...

Homework Statement Let S and S' be two inertial frames of reference where S' is moving at a velocity of 0.6c relative to S. When x = x' = 0, t = t' = 0, where t and t' are time of the clocks on S and S' respectively and x and x' are the x-coordinates of the S and S' frames respectively. An...

Hello everyone :). I'm new here and wasn't sure where to post my physics question so here I am in the homework help section as my question is homework related... The problem I'm having is of very basic nature however I might have some trouble wording it. I understand an event is something that...

If I stand on the surface of the Earth holding an object from my frame of reference I do no work because the object is at rest and the displacement is zero. However from the frame of reference of a second object moving toward the Earth the first object would be moving up and I would be doing...

I know there are many wavefunction collapse models - but with regards to the Copenhagen interpretation the idea is that a measurement will cause something to collapse into a particular state. What does the term "measurement" refer to? It makes one think of only something that a conscious being...

A person is inside a car. This person is not using the seat belt. The car crashes with a solid wall and decelerates quickly. The person, due to inertia, keeps moving until stopped by the wind shield. I want to analyze the movement of this person after the crash, but I am troubled...

Hi, before I question let me say I'm new both to this site and Physics in general, as such please forgive any ignorance on my part. I was given an example of time difference in regards to a 'my twin traveling at near the speed of light' scenario and I'm having trouble reconciling some of the...

I have a question about Earth's rotation around its own axis. Earth rotates at around 1000 miles per hour. However, if I stand in an open field and let a balloon float beside me in mid-air, I wouldn't expect the balloon to fall away (or appear to fly away) at that speed when I let go of it. I...

I'm hoping you can help with a debate I'm having with a friend regarding whether throwing a ball in a headwind is the same or different from throwing a ball from a moving platform (lets say an open boat). If you want some numbers, could you please work with these: For the static throw, can...

Homework Statement In frame F there are two lights on the x-axis at D and -D (D=0.6x10^9 m ) which flash simultaneously when t=0. There is another frame F' which moves at v=0.8c in standard configuration with F. I need to work out when observers standing at the origin of both frame F and F'...

I got stuck going over the derivation of fictitious forces in rotating frames. see specifically http://en.wikipedia.org/wiki/Rotating_reference_frame#Time_derivatives_in_the_two_frames this page to see the proof I'm talking about (sorry i'd love to be able to explain it by myself but...