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What will be the horizontal acceleration

  1. Oct 7, 2015 #1
    1. The problem statement, all variables and given/known data
    a 4.00-kg block is sliding up the plane on a 30 degree incline. If the coefficient of kinetic friction between the block and the inline is .700. What will be the acceleration of the block if a 50-N horizontal force pushes on the block?

    2. Relevant equations

    50 - mgsin(30) - Uk*mg*cos(30) = ma

    3. The attempt at a solution

    I am getting answer 6.65 something whereas the correct answer is 4.40 m/s.
    I suck at this topic. This is the weakest point I would appreciate your help.
    Last edited by a moderator: Oct 7, 2015
  2. jcsd
  3. Oct 7, 2015 #2


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    Staff: Mentor

    It seems like your setup is close. can you post all of your work so we can check it?
  4. Oct 7, 2015 #3
    50 - 4.0*9.8*sin(30)-4.0*0.7*9.8*cos(30) = 50 - 23.76 = 26.64
    26.64/4.00 = 6.56 m/s^2
  5. Oct 7, 2015 #4


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    Looks like you've worked the problem for the case where the 50 N force acts parallel to the incline. But the force is acting horizontally.
  6. Oct 8, 2015 #5
    So what will be the equation if the force is acting horizontal?
  7. Oct 8, 2015 #6


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    When you dealt with the weight mg, you broke it into components parallel and perpendicular to the slope. Do the same for the 50 N force.
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