Evidence of Special Relativity

[webb202]

I know that the example of time dilation and length contraction due to Special Relativity is usually given as the mountain top / sea level decays of muons created by cosmic rays but what is the evidence for mass change?

 

[ShayanJ]

Actually mass change is not one of the things that SR predicts, its just something that some textbooks on relativity introduce and I don't know why they do that because they never use it.
Its only that linear momentum and kinetic energy are different for different inertial observers which is like Newtonian mechanics just the transformation is different.

 

[Nugatory]

I know that the example of time dilation and length contraction due to Special Relativity is usually given as the mountain top / sea level decays of muons created by cosmic rays but what is the evidence for mass change?

From the FAQ at the top of this forum: http://www.edu-observatory.org/physics-faq/Relativity/SR/experiments.html#electron_mass_variation

 

[PhysicistMike]

...what is the evidence for mass change

When designing particle accelerators the designers need to take the relativistic mass increase into account. See the outreach page at the Large Hadron Collider at
http://lhc-machine-outreach.web.cern.ch/lhc-machine-outreach/lhc-machine-outreach-faq.htm

Basically the relativistic mass of a particle increases with velocity and tends to infinity as the velocity approaches the speed of light.

UCSB Science Line sq test
http://scienceline.ucsb.edu/getkey.php?key=1571

Now if you were traveling along with the object, even at the speed of light, it would appear to have its ordinary, rest mass. It's only to the outside world that it appears to have a greater mass. In other words, it's only if the object is moving *relative to you* that you see a difference--which is why we call it relativity. If you're moving along with the object, we say that you are in the object's reference frame. A stationary observer has a different reference frame.

Of course, it may be possible that special relativity is wrong, and something else happens at extremely high velocities. But big particle accelerators like at Stanford and in Switzerland use special relativity every day, and it's been perfectly correct even for the fastest particles we can accelerate.

See also
http://en.wikipedia.org/wiki/Cyclotron
http://en.wikipedia.org/wiki/Particle_accelerator
http://hyperphysics.phy-astr.gsu.edu/hbase/particles/cyclo.html
http://galileoandeinstein.physics.virginia.edu/lectures/mass_increase.html

Actually mass change is not one of the things that SR predicts, its just something that some textbooks on relativity introduce and I don't know why they do that because they never use it.

Where did you get the idea that they never use it? Just look above. I've also seen many other examples of it. For example; A simple relativistic paradox about electrostatic energy, Wolfgang Rindler, Jack Denur, Am. J. Phys., 56 (9), September 1988, page 795.

 

[Devils]

Actually mass change is not one of the things that SR predicts, its just something that some textbooks on relativity introduce and I don't know why they do that because they never use it.
Its only that linear momentum and kinetic energy are different for different inertial observers which is like Newtonian mechanics just the transformation is different.

Correct me if I'm wrong, but I though mass change had been derived in the late 1800s. The example I seem to remember is change in mass when the energy in a spring changes.

 

[PhilDSP]

Correct me if I'm wrong, but I though mass change had been derived in the late 1800s. The example I seem to remember is change in mass when the energy in a spring changes.

Thomson, Joseph John (1893), Notes on recent researches in electricity and magnetism on Internet Archive, Oxford: Clarendon Press
http://www.archive.org/details/notesonrecentres00thom

[p. 21] "When in the limit v = c, the increase in mass is infinite, thus a charged sphere moving with the velocity of light behaves as if its mass were infinite, its velocity therefore will remain constant, in other words it is impossible to increase the velocity of a charged body moving through the dielectric beyond that of light."