SPACE: mass dilation (1 Viewer)

[Rahul]

could someone care to explain to me this statement taken from the csu site:

The more massive it becomes, the more energy that has to be used to give it the same acceleration, making further accelerations more and more difficult. The energy that is put into attempted acceleration is instead converted into mass. The total energy of an object is then its kinetic energy plus the energy embodied in its mass.

the bit underlined is what i dont get....

thanks!

 

[Dangar]

I think this is mass dilation

So when it's accelerating you keep feeding energy into this huge blob but by e=mc^2 all your energy just keeps getting converted to mass so it requires more energy which once again is converted to mass...etc. it's a vicious cycle

 

[Rahul]

oh ok...i think it would be clearer if it was E=E_k+mc².

so if the energy keeps getting converted into mass, are you talking about a limit to the amount that can be converted before energy can be converted to kinetic energy?
in other words, as you input the energy, it would be converted into mass. after, say 75% has been converted to mass, the rest is then converted to kinetic energy. as it is accelerated more, the level of energy required to balance out the mass increases?

figure out that australia!

 

[-X-]

Originally posted by Rahul

so if the energy keeps getting converted into mass, are you talking about a limit to the amount that can be converted before energy can be converted to kinetic energy?
in other words, as you input the energy, it would be converted into mass. after, say 75% has been converted to mass, the rest is then converted to kinetic energy. as it is accelerated more, the level of energy required to balance out the mass increases?

No, as its mass increases, more energy is required to accekerate the object. But that energy has turned into mass once again so even more energy is required to accelerate it. That energy has also turned to mass...and so on goes for ever until (ie will never reach "c"). At the same time, theres length contraction. So mass increases, length shortens and gets to the point where it will turn into a black hole.

 

[BlackJack]

Mass dilation...

HMmm... okay, the main idea is impossibility of accelerating to light speed. As you approach it, the apparent mass of the object increases. This 'increase' in mass comes from the energy you used in acceleration, i.e. not all the energy you put in to accelerate goes to speed.

This also increases the energy required to accelerate the mass further, etc. It's simultaneous.

 

[Shoey]

It also relates to the conservation of mass/energy - the extra mass due to mass dilation can't just appear out of nowhere. It has to come from the energy you put in to the system to accelerate it.

 

[Dangar]

Originally posted by Rahul
so if the energy keeps getting converted into mass, are you talking about a limit to the amount that can be converted before energy can be converted to kinetic energy?
in other words, as you input the energy, it would be converted into mass. after, say 75% has been converted to mass, the rest is then converted to kinetic energy. as it is accelerated more, the level of energy required to balance out the mass increases?

This sounds like chemistry where you get some sort of equilibrium happening! But I don't think that happens at all, you just reach a certain speed (the speed of light) where all extra energy you put in is simply converted to mass,and none becomes 'kinetic' energy and no matter how much energy you put in it will all get converted to mass. You cannot increase it's speed.

 

[Rahul]

dangar, i get what you mean. but i am sure some of it would have to be converted to E_k, because with "none becomes 'kinetic' energy and no matter how much energy you put in it will all get converted to mass" how will it accelerate?

 

[Shoey]

Originally posted by Rahul
dangar, i get what you mean. but i am sure some of it would have to be converted to E_k, because with "none becomes 'kinetic' energy and no matter how much energy you put in it will all get converted to mass" how will it accelerate?

It won't. That's the point, and that's why the speed of light is the ultimate speed limit of the universe (except maybe for tachyons).

With the effects of mass dilation, it would take an infinite amount of energy to accelerate an object with mass up to light speed.

 

[Constip8edSkunk]

consider the formula, m_v = m_o * / sqrt[1 - v^2 / c^2]

when v->c ; m_v->infinity

hence th function is asymptotic and the mass can never be accelerated up to c as it would require an infinite amount of energy to b inputted(which are transformed into mass)

 

[Rahul]

i understand that.

ok so what if it isnt to be accelerated up to c? say just .5c.

how is the energy distributed between kinetic and converting to mass?