[Relativity] Energy and momentum question

  • #1

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 cant get an expression entirely in terms of v or p.
Also how do you get the proper math equations on here? Are the tags [itex]?
 
Last edited:

Answers and Replies

  • #2
Dick
Science Advisor
Homework Helper
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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 cant get an expression entirely in terms of v or p.
Also how do you get the proper math equations on here? Are the tags [itex]?
Here's a TeX tutorial. https://www.physicsforums.com/showpost.php?p=3977517&postcount=3 Try just using the second equation. You know E and you can look up the mass of the proton. That will get you p.
 
  • #3
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!
 
  • #4
Dick
Science Advisor
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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.
 
  • #5
jtbell
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Try just using the second equation.
And make that E^2, not E, on the left-hand side. :wink:
 
  • #6
Dick
Science Advisor
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And make that E^2, not E, on the left-hand side. :wink:
Good point!
 

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