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!

Kinematic question

  1. Apr 28, 2010 #1
    1. The problem statement, all variables and given/known data
    A body of mass m is thrown upward with intial velocity u, in a medium which exerts a resistance force of mkv. Express, in term of g, k and u, the time taken for the body to reach its maximum height


    2. Relevant equations



    3. The attempt at a solution

    a = -g - kv
    dv/dt = -g - kv
    -dv/(g+kv) = dt
    t = -1/k ln|g+kv| +c
    when t = 0, v=u
    c = 1/k ln|g+ku|
    t = -1/k ln|g+kv| + 1/k ln|g+ku|
    At maximum height, v = 0
    Thus t = -1/k ln|g| + 1/k ln|g+ku|
    Is my working correct?
     
  2. jcsd
  3. Apr 28, 2010 #2
    looking quickly i think so....... cant see any problems
     
  4. Apr 28, 2010 #3
    wait... if taking gravity as negative the resistive force would be + first equation?....
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Kinematic question
  1. Kinematics Questions (Replies: 4)

  2. Kinematics Question (Replies: 6)

  3. Kinematic Question (Replies: 2)

Loading...