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Homework Help: Finding the magnitude of force P

  1. Nov 24, 2016 #1
    1. The problem statement, all variables and given/known data

    2. Relevant equations
    F = ma

    3. The attempt at a solution

    My value for P does not make any sense. Why is this so?
  2. jcsd
  3. Nov 24, 2016 #2
    I think you may have forgotten one of the vertical forces.
  4. Nov 24, 2016 #3
    Yeah, I'm almost certain that's the issue. I think it's the normal force, but what is the value of that force in this case?
  5. Nov 24, 2016 #4
    Yes, you forgot the normal force when you summed the vertical forces. But I don't know what the value of that force is. You will just have to use a variable, FN, until you solve the equations and find its value.
  6. Nov 24, 2016 #5
    Oh right, my bad. So for vertical forces my equation ends up being Psin10 - 70cos45 + Fn = 0. From the horizontal forces equation I calculated P to be 57.369...

    Then, Fn = 39.535...

    To sum it up, P = 57.4 and Fn = 39.54. These values satisfy both equations, though do you have any idea what reaction force they are referring to?
  7. Nov 24, 2016 #6
    That looks right. I'm not sure but "reaction force", probably means the normal force.
  8. Nov 24, 2016 #7
    Alright that's what I was thinking as well, no idea what else it could be. Thanks for the help.
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