Special Relativity, equation help needed

punkstart
Messages
4
Reaction score
0
Given that E2 = c2p2 + mo2c4-----------(1);
where p represents the relativistic momentum p=\gammamou,
show that m=(p2c2-T2)/(2Tc2) where m is the relativistic mass of the particle,and T it's kinetic energy.



Homework Equations



E= T+moc2-------(2)

The Attempt at a Solution



I start by saying p2c2= E2-mo2c4 (from (1)), subtracting T2 from both sides gives
p2c2 -T2 = E2-mo2c4-T2 . Now using (2) i expand E;

p2c2 -T2= (T+moc2)2-mo2c4 -T2 which gives
p2c2 -T2= T2+2Tmoc2+mo2c4 -mo2c4 -T2; simplifying

p2c2 -T2 = 2Tmoc2 Now dividing by 2Tc2 gives

(p2c2-T2)/(2Tc2) = (2Tmoc2)/(2Tc2) I now have the required LHS of (1),

This yields (p2c2-T2)/(2Tc2) = mo , NOT m !

Where have i gone wrong !??
 
Physics news on Phys.org
Your work looks fine to me. The problem appears to be wrong.
 
Thread 'Need help understanding this figure on energy levels'
This figure is from "Introduction to Quantum Mechanics" by Griffiths (3rd edition). It is available to download. It is from page 142. I am hoping the usual people on this site will give me a hand understanding what is going on in the figure. After the equation (4.50) it says "It is customary to introduce the principal quantum number, ##n##, which simply orders the allowed energies, starting with 1 for the ground state. (see the figure)" I still don't understand the figure :( Here is...
Thread 'Understanding how to "tack on" the time wiggle factor'
The last problem I posted on QM made it into advanced homework help, that is why I am putting it here. I am sorry for any hassle imposed on the moderators by myself. Part (a) is quite easy. We get $$\sigma_1 = 2\lambda, \mathbf{v}_1 = \begin{pmatrix} 0 \\ 0 \\ 1 \end{pmatrix} \sigma_2 = \lambda, \mathbf{v}_2 = \begin{pmatrix} 1/\sqrt{2} \\ 1/\sqrt{2} \\ 0 \end{pmatrix} \sigma_3 = -\lambda, \mathbf{v}_3 = \begin{pmatrix} 1/\sqrt{2} \\ -1/\sqrt{2} \\ 0 \end{pmatrix} $$ There are two ways...
Back
Top