Can this event vary relatively?

[Hawkingo]

Suppose we take a charged particle and a magnet and place them at some particular distance apart .Now let's take 2 frame of reference.

[the charged particle and the magnet are in rest with respect to each other through out the whole event]{both of the frames are inertial}

frame(a): this frame is in rest with respect to the charged particle

frame(b): this frame is in motion with respect to the charged particle

now in frame(a) there is no change in the magnetic field due to the charged particle

now in frame(b);; As in this frame the charged particle is in motion.so it will generate a magnetic field,and if we assume the velocity is high enough to attract(let's say it is attraction in this case,if it will be repulsion then the result will be the opposite,but that will still come in this question) the magnet then after time(T) the both object will touch each other.

now after time(T) from the start of the event;

1.in frame(a) the charged particle and the magnet are at the same distance from each other as they were from the start of the event.

2.in frame(b) the charged particle and the magnet are touching each other.

now my doubt is ,is the result is true and if wrong what is the fault in my assumptions or in the theory?

thank you for answering.

 

[PeterDonis]

if we assume the velocity is high enough to attract the metal piece

Why would the magnetic field attract the metal piece?

 

[Hawkingo]

Why would the magnetic field attract the metal piece?

sorry,I corrected the post.Now can you please answer?

 

[PeterDonis]

I corrected the post.Now can you please answer?

Still the same question: why would the magnetic field attract (or repel) the metal piece? You need to think about why you assumed that one or the other would happen in the "moving" frame. Hint: the metal piece is not charged (if it were, it would move relative to the charged particle in the "rest" frame), so why would it be affected by a magnetic field?

 

[Hawkingo]

Still the same question: why would the magnetic field attract (or repel) the metal piece? You need to think about why you assumed that one or the other would happen in the "moving" frame. Hint: the metal piece is not charged (if it were, it would move relative to the charged particle in the "rest" frame), so why would it be affected by a magnetic field?

sir please,reread my post,I said the magnet in the edited post.

 

[PeterDonis]

I said the magnet in the edited post

The question is still the same. Why do you think the magnet will either be attracted by or repelled by the magnetic field of the charged particle? (Have you actually tried to write down what the magnetic fields of the charge and the magnet look like in the moving frame?)

 

[Hawkingo]

The question is still the same. Why do you think the magnet will either be attracted by or repelled by the magnetic field of the charged particle? (Have you actually tried to write down what the magnetic fields of the charge and the magnet look like in the moving frame?)

because , the charged particle would create a magnetic field,which when interacts with the magnetic field of the magnet will cause attraction or repulsion.

 

[PeterDonis]

when interacts with the magnetic field of the magnet will cause attraction or repulsion.

Why? Once again, have you actually tried to write down what the magnetic fields look like in the moving frame? You appear to be using a heuristic of "magnetic fields always attract or repel each other". It isn't that simple.

 

[Hawkingo]

Why? Once again, have you actually tried to write down what the magnetic fields look like in the moving frame? You appear to be using a heuristic of "magnetic fields always attract or repel each other". It isn't that simple.

sorry if my assumption was wrong,I tried to find what the field would look like in the moving frame.can you please correct me and show what actually happens in the moving frame relativistically ?

 

[Dale]

frame(a): this frame is in rest with respect to the charged particle

Here there is no force on the charge. Therefore the four-force is zero. When a covariant object is zero in one frame then it is zero in all frames. Therefore the electromagnetic force is zero in all frames.

 

[Hawkingo]

Here there is no force on the charge. Therefore the four-force is zero. When a covariant object is zero in one frame then it is zero in all frames. Therefore the electromagnetic force is zero in all frames.

You said if the value of the a co variant property is zero in one frame, then it will be zero I am other frames. So let's say an charge is moving in a lab and creating a magnetic field.Now a person moves in opposite direction to that charge with same velocity,, so for his frame everything is zero because the charge is in rest, and there is no absolute frame. So according to you there should be no magnetic field in the lab. Right?

 

[weirdoguy]

Mind you, magnetic filed does not form a four-vector. Nor does electric fileld.

 

[Ibix]

So according to you there should be no magnetic field in the lab. Right?

No. Neither electric nor magnetic fields are covariant. The electromagnetic field is the covariant object - some frames will break this down as no electric field and some magnetic field, and others as some electric field and some magnetic field.

This is one explanation for why the electric field of the charge becomes electric and magnetic in the frame where the charge is moving. What do you think happens to the magnetic field of the magnet in a frame where the magnet is moving? How do you think this will affect things?

 

[Dale]

You said if the value of the a co variant property is zero in one frame, then it will be zero I am other frames.

Yes.

So according to you there should be no magnetic field in the lab. Right?

No. Note, the magnetic field is not a covariant object. The relevant covariant object is the Faraday tensor which contains both the electric and magnetic fields.

If the Faraday tensor is 0 in one frame then it is 0 in all frames. Meaning that if there is no magnetic field and no electric field in one frame then there will be no magnetic field and no electric field in any other frame.

so for his frame everything is zero because the charge is in rest

The magnetic field is 0 but the electric field is non-zero, so the covariant Faraday tensor is non-zero in this scenario.

 

[PeterDonis]

a person moves in opposite direction to that charge with same velocity,, so for his frame everything is zero because the charge is in rest

Huh? How would the charge be at rest in this person's frame if he's moving in the opposite direction to the charge?

 

[Hawkingo]

Huh? How would the charge be at rest in this person's frame if he's moving in the opposite direction to the charge?

The charge is also moving in the lab.

 

[PeterDonis]

The charge is also moving in the lab.

So what? You said the person is moving in the opposite direction to the charge. So how can the charge possibly be at rest relative to the person?

 

[Hawkingo]

So what? You said the person is moving in the opposite direction to the charge. So how can the charge possibly be at rest relative to the person?

Sorry. I meant to say same direction

 

[sweet springs]

1.in frame(a) the charged particle and the magnet are at the same distance from each other as they were from the start of the event.

2.in frame(b) the charged particle and the magnet are touching each other.

1. Right
The charged particle generate electric field.
The magnet generate magnetic field.　　　The both do not generate force between.

2. Hum...
The moving charged particle generate electric field and magnetic field.
The moving magnet generate magnetic field and electric field.　　　
If you go into detail of it, you should find the total sum do not generate force either.