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!

Angle of Vector

  1. Jan 31, 2014 #1
    1. The problem statement, all variables and given/known data

    Find Beta of <60,-50,40>

    2. Relevant equations

    Cosine β = Ay/lAl


    3. The attempt at a solution

    lAl = 87.74964387

    So its arccos(-50/87.75) = 124.62

    express to 2 significant figures and it keeps telling me im wrong. I rounded to 125. kept at 124.62.. etc.
     

    Attached Files:

  2. jcsd
  3. Jan 31, 2014 #2
    And i got the answer book telling me this
     

    Attached Files:

  4. Jan 31, 2014 #3

    PhanthomJay

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    The book answers are clearly expressed to three significant figures. What is your correct response for the angle you determined expressed to two significant figures?
     
  5. Jan 31, 2014 #4
    Online it tells me to do 2 sig figs.
     
  6. Jan 31, 2014 #5

    And it's 125 degrees
     
  7. Jan 31, 2014 #6

    PhanthomJay

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    No, that is three significant figures. What is 124.62 degrees expressed to two significant figures??
     
  8. Jan 31, 2014 #7

    I honestly don't know because it clearly has 3 at 125
    How would I make that 2 sig figs
     
  9. Jan 31, 2014 #8

    PhanthomJay

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    I am not an expert on significant figure rules, but you can find them through Google and other search engines. But here is a hint: 141.635 rounded to four sig figs is 141.6. If rounded to three sig figs it is 142; that same number rounded to two sig figs is 140. And that same number rounded to one sig fig is 100.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Angle of Vector
  1. Vector angle (Replies: 12)

  2. Angle of Vector (Replies: 3)

  3. Vector Angles (Replies: 3)

  4. Angle of a Vector (Replies: 4)

  5. Angle of vector (Replies: 4)

Loading...