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Homework Help: Physics Problem: Work-Kinetic Frictional Force

  1. Oct 12, 2004 #1
    A 280 N force is pulling an 80.0 kg refrigerator across a horizontal surface. The force acts at an angle of 18.0° above the surface. The coefficient of kinetic friction is 0.200, and the refrigerator moves a distance of 6.00 m.
    (a) Find the work done by the pulling force.
    1.60*10^3 J
    (b) Find the work done by the kinetic frictional force.

    I got the answer for Part A right, but I can't seem to get the answer for part B. The answer i got for B is 940.8. I used the equation: W= -coefficient of kinetic friction*mg*distance but the answer is wrong. Am I using the wrong equation for Part B?
  2. jcsd
  3. Oct 12, 2004 #2
    Looks right. Remember friction does negative work here, so your final anwer needs to be negative (remember to use a positive value of g for this to work). Other than that, try different values of g, like 9.81, 9.8, 10, as these are all used by various texts.
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