1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Electric forces and Electric fields question on x and y components

  1. Jul 21, 2011 #1
    1. The problem statement, all variables and given/known data

    please see the pictures!

    2. Relevant equations

    F=k(q1)(q2)/r^2



    3. The attempt at a solution

    okay, I am just curious as to why t cos theta and mg are x components when they are clearly on the y axix!
    I thought you used cos for x components and sin for y components
     

    Attached Files:

    • dd.jpg
      dd.jpg
      File size:
      33.9 KB
      Views:
      102
    • ddd.jpg
      ddd.jpg
      File size:
      35 KB
      Views:
      90
  2. jcsd
  3. Jul 21, 2011 #2
    guys I know im a DA, i barely got by in physics I and I was able to get by without knowing how to do these type of problems, now I cant plz help!
     
  4. Jul 21, 2011 #3
    The cosine of theta is the adjacent side of the triangle divided by the hypotenuse. With theta defined to be where it is in this problem, T cos theta is the vertical component of the tension.
     
  5. Jul 22, 2011 #4
    Where is it written that they are on X axis .... looks on Y to me
    Maybe they took X as Y and Y as X

    OP's asking why the vertical component is called X component
    read question again
     
  6. Jul 22, 2011 #5
    I already read the question and the images about ten times before answering. It sounds to me like a teacher may have pounded it into the student's head that x means horizontal and then always take the cos, y means vertical and then always take the sin. I have heard some teachers say that, although it is wrong. The cure for the confusion is to identify the triangle and remember the "sohcahtoa" definitions of sin and cos.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook