Pulling a box by a 10N force

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  • #1
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Homework Statement


A 2.0 kg box is pulled along a horizontal plank by a 10N force parallel to the direction of motion. The rate of acceleration is 0.50 m/s^2. Find the coefficient of kinetic friction.

I think we use the formula: coefficient of friction = F (so 10) / N.
But I am not sure how to use the acceleration and the N variable.


Homework Equations


F - μk mg = ma
10 - 2(9.8)μk = 2 x 0.5

Would this be the correct way to go?

Thanks!
 

Answers and Replies

  • #2
PhanthomJay
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Homework Statement


A 2.0 kg box is pulled along a horizontal plank by a 10N force parallel to the direction of motion. The rate of acceleration is 0.50 m/s^2. Find the coefficient of kinetic friction.

I think we use the formula: coefficient of friction = F (so 10) / N.
But I am not sure how to use the acceleration and the N variable.


Homework Equations


F - μk mg = ma
10 - 2(9.8)μk = 2 x 0.5

Would this be the correct way to go?

Thanks!
Yes, but it contradicts what you said in the problem statement.
 
  • #3
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Yes, so I use the second equation? Is the data correctly plugged in?
 
  • #4
cristo
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Yes, so I use the second equation? Is the data correctly plugged in?
Yes it is.
 
  • #5
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I am getting -0.005 as the answer... does it sound right? Where should the acceleration be used?

Thanks for all the help! :)
 
  • #6
PhanthomJay
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I am getting -0.005 as the answer... does it sound right? Where should the acceleration be used?

Thanks for all the help! :)
you have the correct equation, with the given acceleration entered correctly, but your math is off.
[tex]10 -19.6\mu_k = 2(.5) = 1[/tex]
[tex] -19.6\mu_k = -9[/tex]
[tex]\mu_k = ?[/tex]
 
  • #7
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oops, it's 0.46, right?
 
  • #8
PhanthomJay
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