lenght contrac/inertial frames (1 Viewer)

[mr EaZy]

1) for inertial frames what was it that u cant test what frame u are in?
but u can test if u are in a non inertial frame right?

2) can someone explain the lenght contraction thought experiment?

 

[JayWalker]

Intertial frame of references you cannot tell if your travelling at a velocity.. But unfortunately, I am having the biggest mental blank today.. I have 3 stitches in the back of my head, was skateboarding and my dog jumped me lol!!! anyway fell off.. ouch.. so I cant think properly.

I didnt know there was a thought experiment for this one....

 

[Xayma]

An inertial frame it is impossible to tell if you posses a velocity or not (and any magnitude of it) without an external point.

There is a thought experiment but it involves time dilation and is hard to explain without diagrams. Which textbook do you have?

 

[Jase]

Yes you can tell whether you're in an inertial frame or not, just not whether you're moving at constant velocity or at rest. Use the plumb bob experiment (the accelerometer)..

umm.. what's specifically a length contraction experiment? Don't they all involve some degree of relativistic transformation..

 

[gordo]

sitting on a train, a light is on the roof and it bounces to the ground and back up to the roof again

for someone outside the train the light looks as if it travels further because there is the trains velocity too.
therefore the train must length contract so that the light velocity stays constant

 

[Xayma]

Umm thats time dilation.

 

[nit]

Yeh, it involves time dilation, and it is very unlikely that it would come up in an exam - time dilation/ relativity of simultaneity seem much more apt for an exam...

The length contraction thought exp simply involves shining a light from front to back of a train, and quantitatively analysing the different times and lengths experienced by a passenger on the train vs a person on an embankment outside. Its not too complex, but again, i doubt whether this would be asked in preference to a question on a time dilation/ rel of simultaneity thought experiment.

 

[mr EaZy]

thnx again guys,
yeah i thought it involves light shone from the front to back or vice versa,
and the chances of these things getting to the exam is small but worth knowing a rough sketch.

 

[Brad]

Isnt it like.... a train travelling and a light from the back to a mirror at the front and that sorta thing.....

 

[jumb]

Intertial frame of references you cannot tell if your travelling at a velocity.. But unfortunately, I am having the biggest mental blank today.. I have 3 stitches in the back of my head, was skateboarding and my dog jumped me lol!!! anyway fell off.. ouch.. so I cant think properly.

Pwned .

 

[Brad]

lol omg 1337?