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Homework Help: How to calcoulate force applied?

  1. Aug 27, 2012 #1
    1. The problem statement, all variables and given/known data
    if the coefficient of friction between a 30 kg metal block and the floor is 0.16, what force is required to roll this block across the floor at a uniform speed? how much work is done? find : weight of force, normal force, force applied and fricitional force

    2. Relevant equations

    3. The attempt at a solutionso far i only got this
    weight of force = 294
    normal force =294
    frictional force = 47.04

    How do i get force applied?
  2. jcsd
  3. Aug 27, 2012 #2


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    Gold Member

    Uniform speed implies zero acceleration. Have you drawn a free body diagram?
    What does 'weight of force' mean? Given your numbers, I think you mean the gravitational force on the object.
  4. Aug 27, 2012 #3
    to get uniform motion you need to make the net force on the body equal 0
  5. Aug 27, 2012 #4


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    Science Advisor
    Homework Helper
    Gold Member

    Draw the free body diagram. To move the block the applied force has to be greater than or equal to the oposing frictional force. If it's greater than the frictional force the block will accelerate. The problem states it's "uniform speed" so it's not accelerating. Leading to the obvious answer.

    As for "How much work is done" remember that

    Work = force * distance
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