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!

Speed of skydiver

  1. Mar 19, 2011 #1
    If a person has reached terminal velocity (say 50m/s), and he opens his parachute, and I want to find his speed 2 seconds after he opens his parachute, can I do this?

    Solve the equation m dv/dt = mg - kv^2 and substitute k with 1/2 pCdA and substitute the value for p, Cd, and A to find velocity?

    If I can, can I do this shortcut to simplify work?

    The proper way of doing it would be to solve this differential equation m dv/dt = mg - kv^2 given the condition when t = 0, v = 50. But solving that would be a lot of work, and it is easy to make a mistake somewhere as my calculus skills is rusty. I can find a solution for m dv/dt = mg - kv^2 for when t = 0, v = 0 from wikipedia

    http://en.wikipedia.org/wiki/Terminal_velocity

    1ffbd1e8f007cecae13357f5ad624207.png

    Substitute my values in, I get a number, let that be x. The velocity of a freefall object with no air resistance after 2 seconds is 9.8(2) = 19.6 m/s. The velocity slowed by drag can be found by 19.6 - x. Then I just do 50 - (19.6 - x) to get my velocity after 2 seconds.

    If this doesn't work, is there a differential equation solver that will solve my equation? Thanks
     
  2. jcsd
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted



Similar Discussions: Speed of skydiver
  1. Skydiver balloon (Replies: 8)

  2. Speed of sound (Replies: 2)

  3. Speed of shockwaves (Replies: 8)

Loading...