1. Not finding help here? Sign up for a free 30min 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!

How to integrate this?

  1. Feb 3, 2015 #1
    1. The problem statement, all variables and given/known data
    How to integrate dv/dt=g-kv/m?

    2. Relevant equations
    This is ODE.

    3. The attempt at a solution
    dv/(g-(kv/m))=dt
    Now what? I don't know how to integrate the left side.
     
  2. jcsd
  3. Feb 3, 2015 #2

    Mark44

    Staff: Mentor

    The left side can be rewritten as ##\frac{m \ dv}{mg - kv}##. There's a fairly obvious substitution you can use.
     
  4. Feb 3, 2015 #3
    What substitution?
     
  5. Feb 3, 2015 #4
    Never mind. I integrated and got (-m/k)ln abs(gm-kv)+C.
     
  6. Feb 3, 2015 #5
    Now, how to simplify (-m/k)ln abs(gm-kv)=t+C?
     
  7. Feb 3, 2015 #6

    Stephen Tashi

    User Avatar
    Science Advisor

    Are you saying you can't work [itex] \int {\frac{1}{g- \frac{kv}{m}} }dv [/itex] ?


    Could you do something like [itex] \int (3 -5v)^{-1} dv [/itex] ?
     
  8. Feb 3, 2015 #7
    No, now I got it. I simplified and got gm-kv=Ce^(-kt/m).
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: How to integrate this?
  1. How To Integrate This? (Replies: 19)

  2. How to integrate this? (Replies: 1)

  3. How to integrate this? (Replies: 8)

  4. How to integrate this? (Replies: 2)

Loading...