1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Simple conversion I thought?

  1. Feb 21, 2008 #1
    Near earth, the density of protons in the solar wind is 10.0cm^-3, and their speed is 691 km/s.
    To find the current density I need to multiply (nLA)e

    do i need to convert 10.0 protons cm^-3 to 10000000m^-3 because i tried that and it didnt work????
  2. jcsd
  3. Feb 21, 2008 #2


    User Avatar
    Science Advisor

    This is a simple case that you need to use consistent units to get a sensible answer.

    If you really want to use the units km/s for speed then you should use (km)^-3 for your density and expect an anwser in units Amps/(km)^2. Alternatively you could convert the speed to cm/s (leaving density in (cm)^-3) and that would get you an answer in units Amps/(cm)^2.
  4. Feb 24, 2008 #3
    i actually figured it out
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook