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: Physics: Trigonometry

  1. Jan 25, 2005 #1
    A force vector F1 points due east and has a magnitude of 200N. A second force F2 is added to F1. The resultant of the two vectors has a magnitude of 400N and points along the east/west line. Find the magnitude and direction of F2.

    i really don't know what equation I would use to solve this problem.
     
  2. jcsd
  3. Jan 25, 2005 #2

    dextercioby

    User Avatar
    Science Advisor
    Homework Helper

    Write the addition of vectors and then chose 2 axes of coordinates and project it...

    Daniel.
     
  4. Jan 25, 2005 #3

    BobG

    User Avatar
    Science Advisor
    Homework Helper

    What are your choices for equations?

    A vector pointing due East lies on the East/West line. This winds up being the same as doing arithmetic on a number line. You only have two choices for directions (East or West). Each direction would give you a different magnitude. (Double check to see if they specified which direction the resultant was pointing).
     
  5. Jan 25, 2005 #4

    jtbell

    User Avatar

    Staff: Mentor

    They're telling you that

    [tex]\bold {F}_1 + \bold {F}_2 = \bold {R}[/tex]

    They're giving you the values of [tex]\bold {F}_1[/tex] and [tex]\bold {R}[/tex].

    So in order to find [tex]\bold {F}_2[/tex] you need to do this:

    [tex]\bold {F}_2 = \bold {R} - \bold {F}_1[/tex].

    Now, if you've learned how to add two vectors by now, how would you modify the procedure so as to subtract them instead of add them? :uhh:

    If you haven't learned how to add two vectors by now, I suggest you go back and do that before tackling this problem. :wink:
     
  6. Jan 25, 2005 #5
    Thanks for the help. I think the answers are 200N due east and 600N due west
     
  7. Jan 25, 2005 #6

    dextercioby

    User Avatar
    Science Advisor
    Homework Helper

    Yes,the answers are correct.We only hope u've gotten them through a correct method...

    Daniel.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook