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Need help with a question about momentum

  • #1

Homework Statement



How fast would a proton have to travel to have the same momentum as a 6.0-MeV photon

Homework Equations


P= E / C


The Attempt at a Solution


P= E / C
= 6.0-MeV / 3.00x108m/s
 

Answers and Replies

  • #2
Hootenanny
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Homework Statement



How fast would a proton have to travel to have the same momentum as a 6.0-MeV photon

Homework Equations


P= E / C


The Attempt at a Solution


P= E / C
= 6.0-MeV / 3.00x108m/s
Welcome to Physics Forums.

You need to be careful with your units here, your mixing natural units and S.I. units. You need to pick a system and stick to it.
 
  • #3

Homework Statement



How fast would a proton have to travel to have the same momentum as a 6.0-MeV photon

Homework Equations


P= E / C


The Attempt at a Solution


P= E / C
= 6.0-MeV / 3.00x108m/s

What's the problem here? Have you even put in any thought to it?

Yes P = E/c but if you're going to use that you need to make sure your E and c are in SI - that is - m/s and J

Once you find that you can equate that with the momentum of a proton - mv. You can look up the mass of the proton, and solve for v
 
  • #4
That was my problem, I hadn't realized that i had the different units. Thank you!
 
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