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anonymous

  • one year ago

The sled dog must produce a horizontal force of 80 N in order to keep the 160 kg sled moving across level ice at a constant velocity. What is the coefficient of kinetic friction between the sled and the ice?

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  1. anonymous
    • one year ago
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    Ok so the part that confuses me the most is "constant velocity" meaning that there is inertia at work.

  2. anonymous
    • one year ago
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    @ganeshie8

  3. anonymous
    • one year ago
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    I am not too sure if I can just use the given values to go with the kinetic friction....Any ideas people?

  4. anonymous
    • one year ago
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    @nincompoop

  5. anonymous
    • one year ago
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    The constant velocity part is just another way of saying it's in equilibrium. |dw:1439385917192:dw|

  6. anonymous
    • one year ago
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    I bet the coefficient of friction in this case must be 0.5

  7. anonymous
    • one year ago
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    As 80N are required to move an object that weights 160kg

  8. anonymous
    • one year ago
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    By constant velocity they mean that acceleration is 0, and therefore there is no resultant force on the sled, then the force applied by the dog is just enough to balance friction \[\implies f=-80N\] taking the direction of motion of sled as positive direction, then friction will work in opposite direction Now we know that \[f=-\mu.N\]\[\mu=-\frac{f}{N}\]\[\mu=-\frac{-80}{160 \times 9.8}=\frac{80}{160 \times 9.8}\]

  9. anonymous
    • one year ago
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    no. the frictional force must balance the applied force for equilibrium. \[mg \mu_k=80~ N\]

  10. anonymous
    • one year ago
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    Looks like the second explanation is right.

  11. anonymous
    • one year ago
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    It is. they're the same. I was replying to the 0.5 response and we posted at about the same time.

  12. anonymous
    • one year ago
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    So according to the calculation kinetic friction is revealed as 0.05

  13. anonymous
    • one year ago
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    Well that seems pretty low but I guess that's how much kinetic friction is required for the dog to just apply 80N force and have the sled moving ahead.

  14. anonymous
    • one year ago
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    The low coefficient of friction makes sense because 1) the surface is ice and 2) the coefficient of kinetic friction is generally less than the coefficient of static friction because it takes more force to make something move than it does to keep it moving.

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