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Homework Help: Calculate velocity

  1. Oct 12, 2007 #1
    1. The problem statement, all variables and given/known data
    Their is a 2.00 kg steel block on a steel table. What is the velocity of the block after moving 1.20 meters given that the string tension being pull on the block is 17.0 N and the coefficient of kinetic friction of dry steel on steel is .600.

    2. Relevant equations
    I don't really know what these would be for this problem.

    3. The attempt at a solution
    So far, i've figured that the minimum string tension to move the block is 15.7 N using the coefficient of static friction of dry steel on steel is 0.800. T = Mass * Static friction * gravity. T = (2.00) * (.800) * (9.8) = 15.68 ~ 15.7
  2. jcsd
  3. Oct 12, 2007 #2


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    When the block is moving the only friction force it experiences is that of kinetic friction. the equation for the force of kinetic friction is [itex]F_k=\mu_kN[/itex] where the N is the normal force between the object and the surface.

    All you have to do is work out how much much of the Tension is going into acceleating the block (i.e. the tension minus the friction force) and then use the kinematic equations.
  4. Oct 12, 2007 #3
    So I figured out the force of kinetic friction is = .600 * 9.8 which equals 5.88. I then took the tension of 17 and subtracted 5.88 to get 11.12 N. Is that right so far?
  5. Oct 12, 2007 #4
    Ok, I figured it out. Thanks alot! Your a life saver! haha
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