Re: Is relativity relative?

On Jan 31, 10:01 am, leosara...@xxxxxxxxx wrote:
I've checked a lot of threads but I haven't found a clear answer to
this question, so let me see if I got this straight:
Relativity states that there is no absolute space, that all motion is
relative to other bodies. Therefore, no experiment can be performed
which will measure our "absolute velocity", i.e. unrelated to anything
else.
Now consider this experiment: I am inside a rocket with windows
closed. I have an object, let's say a ball. I give the ball a push
with a fixed force and it accelerates with a given acceleration. I can
use m = F/a to calculate its mass.
I fire my rocket to speed up. Now I repeat my experiment and I get a
new value of the mass m' that is higher than m.


No, you get the same value for m.



I repeat the
experiment many times, each time at a higher speed until the mass of
the ball appears to be infinite: no matter how hard I push it, it
won't move. According to Einsteins's equations, I know that at this
point I am moving at the speed of light, without looking outside.
Is this correct?


No, you get the same value for m, no matter what your velocity.


Barry

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