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: Terminal speed. Calculus. Time.

  1. Jan 1, 2013 #1
    1. The problem statement, all variables and given/known data
    An object of mass m falls from rest subject to air resistance force directly proportional to the object's speed, F=-bv, where b is the proportionality constant in N/(m/s) and the negative sign indicates the direction of the force opposite to the direction of the velocity. How long does it take this object to reach half of its terminal speed?

    2. Relevant equations

    a=g-bv/m, a=dv/dt, etc...

    3. The attempt at a solution
    tried, all failed.
  2. jcsd
  3. Jan 1, 2013 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Using the two equations you posted, and eliminating a between them, should give you a differential equation involving v and t. What is it? Can you solve it?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook