implications of mass increase (1 Viewer)

[serge]

what are the implications of mass increase,
time dilation and length contraction

chances are we wont be able to travel fast enough to
experience it

so what are the implications?

apart from the obvious (that this will happen if we travel fast enough)

 

[rama_v]

Mass increase - as the spacecraft increases velocity the mass increases makign it mroe and more difficult to accelerate the spacecraft, until the relativisitc mass becomes infinity at the speed of light. Hence like you said, you cant travel fast enough

Length contraction (apparently) makes the diastances between two locations in space shorter, hence you can travel there quicker. I am doubting the validity of this calim but I think it was in this years catholic or independent trial, in the sample answers

Time Dilation makes space travel useless as by the time the astronauts return their family members and their whole generation would be long dead, hence the mission i pointless (and no one would do it)

 

[Ghost1788]

Length contraction (apparently) makes the diastances between two locations in space shorter, hence you can travel there quicker. I am doubting the validity of this calim but I think it was in this years catholic or independent trial, in the sample answers

whoa nononono....
Length contraction describes the contraction(in length) of the object approaching the speed of light
as velocity of the object increases the length of the object decreases

Length contraction is where the length of a 'moving' rod appears to contract in the direction of motion relative to a 'stationary' observer

 

[serge]

right, so with that idea out...

there's no implication for length contraction?
because its only what someone else sees you as

ie. it wont affect the travellers and what they do

 

[Ghost1788]

yea.......

 

[rama_v]

whoa nononono....
Length contraction describes the contraction(in length) of the object approaching the speed of light
as velocity of the object increases the length of the object decreases

Thats what I thought, and thats what I still believe, just wanted to point out that it was written in one of the trials from this year -> I think they screwed up

 

[serge]

i think only the mass one has any "real" implications
(not being able to accelerate as much)

It's not like it's feasible to send a manned mission out for ages anyway
(food + water weighs too much unless he grows all his food himself)
(and accelerting to realitavistic speeds would kill your astronaut)

anyway getting sidetracked better get back to revision

 

[Jago]

Length contraction (apparently) makes the diastances between two locations in space shorter, hence you can travel there quicker. I am doubting the validity of this calim but I think it was in this years catholic or independent trial, in the sample answers

whoa nononono....
Length contraction describes the contraction(in length) of the object approaching the speed of light
as velocity of the object increases the length of the object decreases

i don't see why both can't be true?

 

[serge]

The universe isnt travelling at that speed
the spaceship is...

Length contraction only affects the object that is moving

 

[jetfan]

and isnt there the issue similar to the twin paradox, the person in the ship cant make measurements because they will be acceleraating, decelerating, so not in an inertial frame of reference, so the measurements are by people outside of the ship, which means as speed-->infinity, wont the spaceship approach a length of zero? meaning it will disappear?

All this is, is theory, so there are several ways to look at is i suppose

 

[Jago]

but from the spaceship's perspective the universe is travelling at that speed

 

[serge]

wont the spaceship approach a length of zero?

to approach a length of zero you must travel at the speed of light...
but all theory and evidence points to c being the limiting speed of the
universe, so I doubt that even theoretically travelling at c is possible

meaning it will disappear?

that's not correct either... only length contracts.. you'll still have a height
and a width, so if you do travel at c your height and width still has to be
observed (i think this is where we get a tear in the fabric of space-time or
something )

but from the spaceship's perspective the universe is travelling at that speed

no, that doesnt make sense

 

[Ghost1788]

just a thought...dont black holes acceleterate objects to or near the speed of light therefore the objects suffer from length contraction...this would explain y everything that gets sucked into a blackhole becomes infinitely small...

 

[LostAuzzie]

no, that doesnt make sense

It may not make sense but it's true.
Since all motion is relative, from the spaceship's perspective it is stationary and the universe is moving (or planets etc within the universe)
Much of Einstein's theory of relativity doesn't make sense but it's been proven (e.g: Time Dilation)

 

[serge]

It may not make sense but it's true.
Since all motion is relative, from the spaceship's perspective it is stationary and the universe is moving (or planets etc within the universe)
Much of Einstein's theory of relativity doesn't make sense but it's been proven (e.g: Time Dilation)

Jago was proposing the universe will contract, not that motion is relative

 

[Jago]

in one direction it seems to contract

 

[LostAuzzie]

Jago was proposing the universe will contract, not that motion is relative

But since motion is relative, to the spaceship the universe will contract.
This is because, to the spaceship the universe is moving at that speed and thus is affected by length contraction

 

[serge]

but like someone mentioned earlier, Rama i think?

the universe would contract but it would not shorten the travel time)
a-ha
I think this is the reason why time dilates

If the length of the universe contracts to the traveller,
time must slow down for the traveller because
for another observer the event would not make sense
(I tried my best to make sense of it)

thanks for the feedback everyone

 

[rama_v]

but like someone mentioned earlier, Rama i think?

the universe would contract but it would not shorten the travel time)
a-ha
I think this is the reason why time dilates

If the length of the universe contracts to the traveller,
time must slow down for the traveller because
for another observer the event would not make sense
(I tried my best to make sense of it)

thanks for the feedback everyone

Yeah, I mentioned that the distances in space would contract, making the distance shorter- but again, I don't believe this is true -> i think it was in the sample answers for this years independent paper, but how knowledgeable the people who write thos eexams are is anyones guess. In any case, just stick to time dilation and mass dilation as problems, dont involve length contractoin