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!

Newton's Law

  1. Oct 15, 2014 #1
    • Warning: Homework Template must be used for questions posted in the Homework area.
    An object with a mass if falling with a force that is equal to its own weight of 25 pounds. The air resistance causes a decelerate force equal to 1/2 the velocity of the object at any time. If the object falls from rest, what is the velocity of the object after 8 seconds?

    I'm just confused at the wordings of the question. I just cannot find a way to start.
    I tried to use to formula v(t) = (mg/b)t - (m^2*g / b^2) + m/b*vknot but the formula did not make sense to me. I was wondering if there are any other formulas I could use to solve this problem.
     
  2. jcsd
  3. Oct 15, 2014 #2

    Simon Bridge

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    Start with a free body diagram - draw all the forces on the object, the use Newton's laws.
    You'll end up with a differential equation.
     
  4. Oct 15, 2014 #3
    It is confusing. "Falling with a force" does not make much sense.
    And a force equal to 1/2 the velocity it's definitely nonsense. The units do not match.
    Is this the actual text of the problem?
     
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: Newton's Law
  1. Newton's laws (Replies: 3)

  2. Newton's law (Replies: 8)

  3. Newtons laws (Replies: 3)

  4. Newton's laws (Replies: 5)

  5. Newtons law (Replies: 5)

Loading...