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Homework Help: Two questions, work-kinetic energy related

  1. Feb 27, 2008 #1
    1. The problem statement, all variables and given/known data

    1)A 5.0-kg block slides down a surface inclined 30 degrees with the horizontal. If the coefficient of kinetic friction for the block and the surface is equal to 0.25, at what rate is the friction force on the block doing work at an instant when the speed of the block is 3.0 m/s?

    2) Consideran incline with two locations on the slope, A and B. point A on the incline does not necessarily occur at the top of the incline but does occur before B.
    A 2.0-kg block slides down a frictionless incline from p.A to p.B. A force (magnitude P = 3.0 N) acts on the block between A and B, as shown. Points A and B are 2.0 m apart. If the kinetic energy of the block at A is 10 J, what is the kinetic energy of the block at B?

    2. Relevant equations

    3. The attempt at a solution
    i keep getting incorrect numbers (the questions are multiple choice).
  2. jcsd
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