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Homework Help: Will the box move?

  1. Sep 26, 2010 #1
    Hello people, I just joined up and I have just started to learn Physics by myself. I had originally taken Physics in high school but even though I did not get good marks I really enjoyed the concepts. I am now 28 and have completed a Honours BA in Geography and a Masters in Education. I want to learn Physics for my own personal knowledge and perhaps if possible to teach at the high school level (I think I did bad because I had a poor teacher, but I don't want to make excuses). Well I started looking at resources online and have found a site that provides a good introduction; however, I have stumbled upon a question that is giving me some trouble, here it is:

    1. The problem statement, all variables and given/known data

    You pushed a 1 kg box on floor where u= 0.3. If the force you applied was 5 N, will the box move?

    2. Relevant equations


    Ff=uFn Fn=-mg

    3. The attempt at a solution

    Well I am not sure exactly what the question is asking, I was able to calculate Fn=9.8 and Ff=2.94, but how does that answer the question? In the previous chapters, I worked with mass, acceleration, time, displacement equations, and understand that I may need to combine one or more equations. Do I need to find displacement>0 in order to answer yes/no or am I looking at it wrong?

    Last edited by a moderator: Apr 25, 2017
  2. jcsd
  3. Sep 26, 2010 #2
    In order for the box to move, your applied force (5N) has to be higher than the box's static friction. How would you express this in mathematical terms?
  4. Sep 26, 2010 #3
    Do you mean F>Ff? If so then 5N>2.94N is true and the box moves. Is that correct?
  5. Sep 26, 2010 #4
    Yes, that's correct.
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