Recent content by raymondtco

Oops.. You brought up another question of mine. Hmm.. Let say, we have two stars with gravitational potential energy (or two charges with electric potential energy). As a result, we do have higher mass of this composite system and the extra mass cannot be assigned to either one. Then what would...

Hmm.. I see. So as long as I account for the total mass of a composite system, I do not have to include any other forms of energy since they already considered in terms of mass. Now everything is crystal clear! Thank you all for your effort and patience! It's greatly appreciated! =)

jtbell & DeleSpam: Ahh... I get what you mean. Are you saying the mass for a composite system could be larger than the sum of all its elementary particles because some portion of mass is stored in the interatomic thermal and potential energy, which can be thought of as extra mass? That's why...

Hmm.. Why will we have the discrepancy like this? I thought the person could claim that 18 years ago, Star A just emitted the light and according to the Lorentz transformation, the time for A should elapsed 6 years. What's wrong with this idea? Would you please explain to me in more details...

[Ahh.. I kind of get it. I understand what you are calculating now.] (Before modified.) Wait.. No.. If you are calculating the time difference for the light, then I do not really agree with 0.8c since it is the speed of Star A relative to me. I would use c instead as it is the speed of the...

Hmm.. Yeah, my calculation was wrong in the G. I wonder how you get 0.8*18. Are you subtracting two equations and plug in only the difference? I guess the equation will become: \Deltat = G [ \Deltat' - v\Deltax/c2 ] Therefore, I would get t = \frac{1}{0.6} [ 18 - 0.8c(0.8c*18yrs)/c2]...

Sorry but I don't really agree with your calculation since it should not be 0 for the second term. Let me show you my calculation. Primed variables are with respect to the person, while the unprimed ones are to the Star A. t = G [ t' - vx/c2 ] G=0.6 tf = 0.6 [ t'f - 0.8c*3.6ly/c2 ] =...

Thanks for you detailed explanation. However, your answer brings me some more questions. Relativistic Kinetic Energy is Ek= Gmc2 - mc2 I think of Gm as the new mass (relativistic mass) and therefore, compared with rest mass the energy gained is just the energy associated with the increase...

Sure! What I did was that, when the person sees the light, it is 3.6 ly apart from the Star A. And, light is traveling at c whereas the Star travels at 0.8c relative to the person. Therefore, it takes ""3.6 ly / (c-0.8c) = 18 years "" for the ligth pulse and A to be 3.6 ly apart from each...

jtbell: According to my instrucor, thermal and potential energy inside the clay is nothing but the increase in mass. Therefore, it's back to the increase in mass again. Is that right? Ich: Yeah, that's what I believe. I thought the energy would go into some other sorts of paticles and their...

Homework Statement There are two stars A and B relatively at rest in the universe with the proper length of 12 ly. A person is traveling at the speed 0.8c relative to the stars along the extended line of stars A & B (towards A). When the person gets to the midpoint between A & B, he sees a...

My instructor continuously insists on the idea that I don't understand/believe. Therefore I hope the people here could verify/discuss with me. Regarding the conservation of mass-energy, he took an example of the head-on-head collision of two identical clay lumps with same speed. What he...