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A Relatively Relevant Relativity Guide

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jakesilove:

--- Quote from: sianjohnson on January 28, 2017, 09:27:24 pm ---Hey Jamon

I was just taking a look over special relativity when I stumbled over your guide!

My physics teacher asked the class to take a look at specific examples of evidence of time dilation, length contraction and relativistic mass. You mentioned a couple of examples in the guide which I had managed to find but I was wondering if you knew about any awesome ones that are more obviously linked to one area??

More importantly is it likely that they'll ask for specific evidence in the HSC exam??

Cheers,

Sian

--- End quote ---

Hey! They definitely can ask for specific evidence in the exam, but generally it will be for 'relativity' in general, not a specific component within relativity. So, I would probably have two or three examples up your sleeve. The ones I remembered are below.

Atomic clocks

On Earth, we perfectly synced two atomic clocks. What are they? Basically, just super precise, super accurate clocks! We put one on a jet, and left one on the ground. The jet flew around the earth super fast a couple times, then came back to the ground. If you compare the two clocks, you'll see that the one that travelled faster actually experienced/measured less time, despite the fact that the clocks SHOULD read exactly the same! This is an example of time dilation.

Muons

There are these tinsy tinsey particles called muons. They have a pretty short half life (ie. they disappear very rapidly). We can measure the speed with which muons hit the ground and, if we use that speed to determine the time the muons must have taken to travel through the atmosphere, we would EXPECT them to have decayed much more quickly. ie. We might measure 10,000 muons, when we only expected to measure 4,000 muons (because the rest should decay). The muons are actually experiencing time slower, and also seeing the distance between the atmosphere and the ground as shorter. Pretty damn cool!

Accelerated particles

We accelerate particles to really, really fast speeds. We would expect that

F=\frac{1}{2}mv^2

which is the measure of kinetic energy to determine how much force we need to put onto the particle to get it moving faster. But, as the velocity increases, we find we need to put MORE energy than expected into it to continue it's acceleration! Weird! Well, looking at the equation above, the only possible explanation is that the mass has increased! This is an example of relativistic mass dilation.

Jake

Sukakadonkadonk:
Hey Jamon,

I see that you have defined inertial and non-inertial frames of reference up there but I am wondering if you could give a super succinct definition that could be appropriate for exams, that is, if the one you gave was not.

Thank you.

kiwiberry:

--- Quote from: Sukakadonkadonk on February 23, 2017, 05:32:13 pm ---Hey Jamon,

I see that you have defined inertial and non-inertial frames of reference up there but I am wondering if you could give a super succinct definition that could be appropriate for exams, that is, if the one you gave was not.

Thank you.

--- End quote ---

All you have to write is that an inertial frame is one that is not accelerating, and a non-inertial frame is one that is accelerating :)

jamonwindeyer:

--- Quote from: kiwiberry on February 23, 2017, 05:47:11 pm ---All you have to write is that an inertial frame is one that is not accelerating, and a non-inertial frame is one that is accelerating :)

--- End quote ---

2 marks out of 2 - Love your work as always kiwiberry! ;D

arunasva:
Hello, do we have to know all the thought experiments ? Like mass dilation ?

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