[Relativity] Energy and momentum question

[radiator0505]

Homework Statement

Write down a relation between the total relativistic energy, mass and momentum of a
particle. An antiproton has a total energy of 5.00 GeV. Calculate its momentum and its
speed.

Homework Equations

E = γmc^2
E = (cp)^2 +(mc^2)^2
p = γmv

The Attempt at a Solution

I've tried subbing everything in and playing around with the algebra but I can't get an expression entirely in terms of v or p.
Also how do you get the proper math equations on here? Are the tags $?$

 

[Dick]

Homework Statement

Write down a relation between the total relativistic energy, mass and momentum of a
particle. An antiproton has a total energy of 5.00 GeV. Calculate its momentum and its
speed.

Homework Equations

E = γmc^2
E = (cp)^2 +(mc^2)^2
p = γmv

The Attempt at a Solution

I've tried subbing everything in and playing around with the algebra but I can't get an expression entirely in terms of v or p.
Also how do you get the proper math equations on here? Are the tags $?$

$<br /> Here's a TeX tutorial. <a href="https://www.physicsforums.com/showpost.php?p=3977517&postcount=3" class="link link--internal">https://www.physicsforums.com/showpost.php?p=3977517&postcount=3</a> Try just using the second equation. You know E and you can look up the mass of the proton. That will get you p.$

 

[radiator0505]

you can look up the mass of the proton

Sorry I should have said, this is a question from an exam a few years ago and it doesn't mention the mass of the proton anywhere in the entire paper. Is there a way to get the answer without knowing m?
Cheers for the tutorial!

 

[Dick]

Sorry I should have said, this is a question from an exam a few years ago and it doesn't mention the mass of the proton anywhere in the entire paper. Is there a way to get the answer without knowing m?
Cheers for the tutorial!

No, you need to know something else besides just the energy.

 

[jtbell]

Try just using the second equation.

And make that E^2, not E, on the left-hand side.

 

[Dick]

And make that E^2, not E, on the left-hand side.

Good point!