Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Z Component of a force

  1. Feb 27, 2010 #1
    What are the components of the 200kN force along, the x, y and z directions?
    http://img7.imageshack.us/img7/1358/72180912.jpg [Broken]

    So, I can find the x and y components, but I dont know how to find the z component, I have been researching on the internet, my text book (Vector Mechanics for Engineers: Statics) and in my lecture notes, but I just cant find how to find the z component.

    Fx = 200cos 41.4 = 150 N
    Fy = 200sin 30 = 100 N
    Fz = ???

    Please HELP!

    P.S. Sorry if the post isnt in the right format, but I need the answer soon and I only just registered..
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Feb 27, 2010 #2


    User Avatar
    Homework Helper

    How did you get Fx=200*cos(41.4)? That's the right answer, but it's not how I would have done the question.

    The projection of the force on the x-z plane is F*cos(30), correct? Now you can split this force, F*cos(30), into its x and z components just like you do with any vector in 2 dimensions.
  4. Feb 27, 2010 #3


    User Avatar
    Homework Helper

    Hi Brophi, welcome to PF.
    F*cos(30) is the projection of F on the xz plane.
    From that you can find z component.
    Can you show your calculation for Fx ? from where did you get 41.4 degree angle?
  5. Feb 27, 2010 #4
    This stuff is all very new and confusing to me but I think I got the the right answer for Fz = 100cos30 = 86.6 and I'm realy not sure how I got to this or 41.4 for Fx... Could someone explain it maybe? sorry for the inconvenience, its just kinda frustrating that I cant figure this out (been trying for a ffew hours straight)...
  6. Feb 27, 2010 #5
    I found it! This forum rules...

    found the answer at https://www.physicsforums.com/showpost.php?p=1439702&postcount=2 [Broken]

    Fx = 200 sin 60 cos 30
    Fy = 200 sin 30
    Fz = 200 sin 60 sin 30

    Thanks for the help!
    Last edited by a moderator: May 4, 2017
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook