Just a big question...

wrote:
There is a guy named Mavis on a space ship. The space ship is at
rest
and he measures the ship to be "60m" long. The ship then accelerates
to a speed of "0.8c", where "c" is the speed of light. Now, due to
relativity Mavis will no longer measure the ship to be "60m".
Instead,
the length of the ship as measured by Mavis will be longer than
"60m".

I'm sure you are all familiar with the equation

"l =3D 1/y * l_o"

where
"l" is the length of the space ship at rest and equals "60m"
"l_o" is the length of the ship travelling at "0.8c" as measured by
Mavis
"y" equals "1/sqrt(1-v=B2/c=B2)"

Now "1/y" equals "0.6".

So "l_0" equals "100m".


No, l_0 =3D l(sqrt(1-v=B2/c=B2)).
So l_0 =3D (60m)(0.6) =3D 36m.

So it becomes shorter to an observer who it is moving relative to.


Now, Mavis can measure the ship in various ways. If he measures the
space ship using light signals he will find that the ship is "100m"
long. However, if he measures the ship with a ruler he will find
that
the ship measures "60m". The reason why the ship hasn't expanded
when
measured with a ruler is because the ruler *itself* has also
expanded!


No. If he uses either light signals or a ruler, he will still measure
60m to him.


This leads to the Big Question:

the Big Question #1: Does this not contradict Einstein's first
postulate, the Principle of Relativity, which states that "the laws
of
physics are the same in every inertial frame of reference." Because
obviously if Mavis can figure out what velocity the ship is
travelling
at then there must be an absolute frame of reference, that is, a
frame
of reference from which to measure the velocity of the ship.


He cannot figure out the velocity of the ship by measuring anything on
board the ship.


Here's another way of looking at it:

We all are familiar with the fact that "relativistic mass" and "rest
mass" are related by the following equation:

"m_r =3D y * m"

where
"m_r" is the "relativistic mass"
"m" is the "rest mass"
"y" equals "1/sqrt(1-v=B2/c=B2)"

Let's say that we have a brick on a scale on the Earth. Right now it
weighs "3 kg". Now, what if by some extraordinary spacial event that
the Earth was sent out into space accelerating till is acquired a
velocity of "0.8c". Now, the relativistic mass of the brick will be
"5
kg". The scale will definetely weigh the brick to be more than "3
kg"!


No scale on the ship will weigh the brick at more than 3 kg. Only if
the brick were to hit something that was stationary relative to its
0=2E8c speed would it hit with an energy as though it weighed 5 kg.


We again return to the Big Question:

the Big Question: Does this not contradict Einstein's first
postulate,
the Principle of Relativity, which states that "the laws of physics
are
the same in every inertial frame of reference." Because obviously if
Mavis can figure out what velocity the ship is travelling at then
there
must be an absolute frame of reference, that is, a frame of reference
from which to measure the velocity of the ship.
----

You can view my paper (which will be completed pending the answers to
this message)

"A Collection of Ideas" at...

...http://www.angelfire.com/un/rv

No. Einstein's postulate is never violated in this example.

Double-A

Hi Double-A True his ruler,and clock stays relative in size,but one
effect that is proven by our great accelerators(not around in Einstien's
time) inertia goes up,and that means even though his scale still can
read he weighs 180 lb going at 99.999999999 of 'c' he now weighs
70,0000 times his rest mass. He died when his space ship past the speed
of 73% of 'c' 73% of 'c' is my personal figure The
figure of 70,000 times heavier came from the Cern lab. Bert

G=EMC^2 Glazier wrote:
Hi Double-A True his ruler,and clock stays relative in size,but one
effect that is proven by our great accelerators(not around in
Einstien's
time) inertia goes up,and that means even though his scale still can
read he weighs 180 lb going at 99.999999999 of 'c' he now weighs
70,0000 times his rest mass. He died when his space ship past the
speed
of 73% of 'c' 73% of 'c' is my personal figure The
figure of 70,000 times heavier came from the Cern lab. Bert

No, his weight or mass really haven't increased. That's why scientists
have moved away from the term "relativistic mass". Only his momentum
has increased. Since there is the speed limit at c, velocity can no
longer increase linearly as you keep adding momentum, but the added
momentum is there.

The additional momentum will in no way affect him while in flight.
Only if he should slam into a stationary brick wall will he do an
amount of damage to it as though he weighed 70,000 x more than his
normal weight (mass).

Double-A