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Homework Help: What formula do I use?

  1. Sep 15, 2005 #1

    wr1015

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    What formula do I use???

    A shopper pushes a 7.3 kg shopping cart up a 13° incline, as shown in Figure 5-21. Find the horizontal force, F, needed to give the cart an acceleration of 1.63 m/s2.
     

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    wr1015, Sep 15, 2005
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  3. Sep 15, 2005 #2

    Tide

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    Use [tex]\vec F = m \vec a[/tex]
     
    Tide, Sep 15, 2005
  4. Sep 15, 2005 #3

    wr1015

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    i did that and got 18.99 N but its being counted as wrong. There are some formulas in my book that show horizontal force as [tex]\sum\\F_{x}=F_{1},_{x}+F_{2},_{x}=F_{1}+F_{2}\cos\theta[/tex] but am not given any forces?? :confused:
     
    Last edited: Sep 15, 2005
    wr1015, Sep 15, 2005
  5. Sep 16, 2005 #4

    Tide

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    You know what the force of gravity is! It's direction is vertical but has a component parallel to the incline. The shopper applies a horizontal force which also has a component parallel to the incline. The sum of the forces parallel to the incline equals mass times acceleration along the incline.

    You should be able to take it from there.
     
    Tide, Sep 16, 2005
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