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Changing components back into general

  1. Dec 7, 2006 #1
    i am having a little problem.

    i have the acceleration in the x direction for an object but do not know how to change it back to regular acceleration.

    please help
  2. jcsd
  3. Dec 7, 2006 #2


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    Homework Helper

    What exactly do you mean by 'regular acceleration'?
  4. Dec 7, 2006 #3
    Amendment to Earlier Question

    Sorry, i am new to this. Here is requested info.

    1. The problem statement, all variables and given/known data
    An 80.0 N box of clothes is pulled 20.0 m up a 30.0 degree ramp by a force of 115 N that points along the ramp. If the coefficient of kinetic friction between the box and the ramp is 0.22, calculate the change in the box's kinetic energy

    2. Relevant equations
    I started by back tracking to find the mass (m=f.w./g)

    Then tried to solve for the sum of the forces in the x direction by doing sigma Fx = -Fw,x+Fp,x

    I solved for Fw,x by

    Fw,x = Fw*sin theta

    and Fp,x by

    Fp,x = Fp*cos theta

    got Fx = -40 + 69.28 = 29.28 N

    From Fw,x I solved for a,x with

    a,x = ΣF,x/m

    a,x = 3.59 m/s2

    3. The attempt at a solution

    is it

    a,x = a cos theta

    a = a,x/cos theta

    a = 3.59/ cos 30 degrees

    a = 4.15 m/s2

  5. Dec 7, 2006 #4
    please see new thread 'Amendment to Earlier Question'

  6. Dec 7, 2006 #5


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    Rather than starting a new thread, please just continue in the same thread you've already created for this question. I have merged the threads together. Please do not create another one.

    - Warren
  7. Dec 7, 2006 #6


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    The change of the kinetic energy of the box equals the work done by all forces along the displacement. Identify the forces acting on the box, draw a free body diagram, and set up the equation of work.
  8. Dec 7, 2006 #7
    thanks for the help

    will be back in a little while
  9. Dec 7, 2006 #8
    Will let you know the results after i receice the homework assignment back on Monday.
  10. Dec 8, 2006 #9
    Thanks to everyone who helped out. I turned in my homework today, after staying up till 10:46 last night
  11. Dec 19, 2006 #10
    thanks to all who helped
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