Engergy & Relativity (1 Viewer)

[MyLuv]

I just wonder that in case they ask for total energy of a moving particle such as electron:
Total E= E+Ek= mc^2 +1/2 mv^2 (but do we use real mass or relative mass ?)

 

[...]

oh no..not relativity again!!


hmm...
i think we will be using relative mass...

 

[jm1234567890]

depends what you put as v

 

[MyLuv]

depends what you put as v

<--- U mean if v=0 then E=mc^2 and if v><0 (eg v=0.5c) then E=mc^2 + 1/2m (0.5c)^2 with m is relative mass ???

 

[MyLuv]

Can some1 help me answer this plz???

 

[ND]

In this case, you can't use that equation to determine KE. KE = E - E_o, where E is total energy, and E_o is rest enery. Total energy is given by E = mc^2/(1 v^2/c^2)^1/2.
.'. KE = mc^2/(1 v^2/c^2)^1/2 - mc^2

 

[Dash]

I don't remember seeing this in the syllabus...
Where abouts is it?

 

[MyLuv]

Originally posted by ND
In this case, you can't use that equation to determine KE. KE = E - E_o, where E is total energy, and E_o is rest enery. Total energy is given by E = mc^2/(1 v^2/c^2)^1/2.
.'. KE = mc^2/(1 v^2/c^2)^1/2 - mc^2

Thx