Forum Home
PC World Chat
 
Thread ID: 56586 2005-04-09 07:54:00 E=mc(c) Renmoo (66) PC World Chat
Post ID Timestamp Content User
343134 2005-04-09 07:54:00 Greetings PressF1, contrary to my thread on teleportation, I would like to ask a question. In Physics, for the letter E in E=mgh, there is a subscript of p for it which stands for "potential". In kinetic energy formula, E=0.5mv(v), there is a small letter k under E, which is an acronym of "kinetic". So, what subscript do I have for E=mc(c)? Thanks and Cheers :) Renmoo (66)
343135 2005-04-09 08:47:00 what is the question asking? Prescott (11)
343136 2005-04-09 09:12:00 I would say 'r' for radiation

Look here for my reasoning (www.wbabin.net)
Myth (110)
343137 2005-04-09 09:37:00 It isn't usual for E to have subscripts p or k. Maybe it is your particular physics reference that is using them for clarity. Energy is energy, to find the velocity of a body falling through a height h, you would equate kinetic energy 1/2mv² to potential energy mgh for example.

Edit: Incidently mythix's reference illustrates why some people think Einstein wasn't all he was cracked up to be. He pliagarised other peoples work without refering to what had gone on before.
Terry Porritt (14)
343138 2005-04-09 11:05:00 what is the question asking?
Sorry, Prescott. I am asking for the type of energy posseses by E=mc(c). Sorry for the confusion. Cheers :)
Renmoo (66)
343139 2005-04-09 13:43:00 These subscripts must be your particular textbook/teacher's notation. There are no 'types' of energy, energy just 'is'.

That said, I'd guess it would be E subscript m, for mass.
Rugrats (6953)
343140 2005-04-09 20:56:00 The "subscript" which doesn't exist would refer th "mass energy" or "binding energy", which refers to the mass deficit (m) used to calculate the value. somebody (208)
343141 2005-04-09 23:40:00 Perhaps a bit of basics, the units of all physical quantities can be expressed in terms of Mass, Length, and Time, M, L, T.

Energy, in whatever form, has the units of work, M.L².T-²

Temperature is also a measure of average energy of atoms/molecules, so also has the dimensional formula for energy, though it is convenient to refer to scales of temperature, like °K.
Terry Porritt (14)
343142 2005-04-11 06:55:00 These subscripts must be your particular textbook/teacher's notation. There are no 'types' of energy, energy just 'is'.

That said, I'd guess it would be E subscript m, for mass.
So, from your view, can mc(c) = 0.5mv(v) ? Cheers :)
Renmoo (66)
343143 2005-04-11 08:26:00 So, from your view, can mc(c) = 0.5mv(v) ? Cheers :)

You can't do that James, because you are confusing rest mass m*, the mass when the velocity is zero, with the relativistic mass m.

Relativistically we have:

m= m*/(1-v²/c²)½

So that when v is small compared with c, total energy E = m*c² +1/2m*v²
Terry Porritt (14)
1