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Homework Help: Sketch the graph of Ff(y-axis) vs Fapp(x-axis)

  1. Nov 18, 2007 #1
    I am pulling my cousin who has a mass of 10kg, geets all bundled up and sits in the sled, which has a mass of 15kg. He yells ready,set,go and I start to pull him across the snow. I am pulling the sled at an angle of 50degrees with respect to the horizontal. Assume that the coefficient of static friction between the sled and the snow is Ms=.2 if I pull him across the snow with a force of 200N, fine the following values.

    A) Find the acceleration of my cousin and the sled WITHOUT FRICTION.
    B) Find the acceleration of my cousin and the sled WITH FRICTION.
    C)If we doubled the mass of the sled and the child, would the acceleration increase, decrease or stay the same?
    D)If we go to the moon, where g=1.63m/s^2, and pulled the child across the same surface (just pretend it's snowing on the moon) would the acceleration increase, decrease, or stay the same?
    E) skept the graph of Ff(y-axis) vs Fapp(x-axis) until Fapp is 500N.

    3. The attempt at a solution

    A) 3.7
    b) 3.16
    c) decrease
    D) increase
    E) I got a straight line where Ff=18.4N from 0 Fapp to 500 Fapp
  2. jcsd
  3. Nov 18, 2007 #2
    I don't know about anyone else, but I'm happy to check your equations, though I don't want to directly check your answer.
  4. Nov 18, 2007 #3
    check my equations i used for each of those? do you want the numbers with them?
  5. Nov 18, 2007 #4
    Doing the algebra is fine. For example (you don't need to use TeX):

    [tex]\sum_i F_i = ma = F_1 + F_2 + F_3...[/tex]

    whatever those forces may be.
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