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I dont understand this, can you help?

  1. Oct 5, 2005 #1
    i have a test on friday and i know these kinds of questions will be on it, but i just cant figure it out. here's a real easy version of those questions and i was hoping you guys could clear up for me the basic way to do this:

    a man finds that a 6N force will pull a toy wagon along a level table at a constant velocity. He also finds that a 42N force will accelerate the same wagon at 3.0m/s2 along the same table. what is the mass of the wagon?

    thanks for your help!
     
  2. jcsd
  3. Oct 5, 2005 #2
    ok, do you have the correct answer for this? i'm assuming there's friction or air resistance or something since when you apply the first force there's no acceleration. So you do SumF= ma and i assume there's some counter force (F) that accounts for the zero acceleration. So, 6N + F= m(0), the mystery counter force, (friction or whatever,) is -6. So, i do SumF= ma again with the second force and our new found counter force, and plug in the given acceleration and solve for mass.
     
  4. Aug 26, 2009 #3
    I am not a teacher and I am not experienced at explaining or solving mathematics problems.
    I reply to hebdens post in order to test my understanding.


    Basically your problem is to solve is F= m*a

    The force was given, and
    The acceleration was given.

    Rearranging the formula may help.

    Forget the first force value of 6N it is irrelevent at first.

    I believe friction can be ignore in this question.

    below is starting point. good luck to those who are trying to solve this 4 years later.

    F=42N
    a=3.0m/s^2
    m=?
     
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