×
Follow Us
Results 1 to 8 of 8

What are the magnitude and direction?

 Jump to latest post
    #1
  1. Join Date
    Sep 2019
    Posts
    2
    Reputation

    What are the magnitude and direction?

    If a = (5, -12), what are the magnitude and direction of a?


    The above question marked me wrong I answered:
    (13, 292.6°)

    I double checked this online and my answer was correct

  2. #2
  3. Uguessus is offline Junior Member Pro Subscriber
    Join Date
    Dec 2019
    Location
    Signal Hill, CA
    Posts
    5
    Reputation
    Quote Originally Posted by csabin View Post
    If a = (5, -12), what are the magnitude and direction of a?


    The above question marked me wrong I answered:
    (13, 292.6°)

    I double checked this online and my answer was correct
    I calculated (13, 337deg). Here is what I have for the angle...270deg + 67deg = 337deg.

  4. #3
  5. csabin is offline Junior Member
    Join Date
    Sep 2019
    Posts
    2
    Reputation
    Quote Originally Posted by Uguessus View Post
    I calculated (13, 337deg). Here is what I have for the angle...270deg + 67deg = 337deg.

    I even went back to a calculator website. The angle should be 360-67.3 = 292.7 degrees because if you think of this even logically the vector would have to be closer to the y axis much closer to 270 degrees. Due to the fact that -12 is much larger then 5.

    Also you can even prove this with a calculation arctan(-12/5) = -67.3 degrees. I’m 1000% positive this is an error on test guide or I have wrote the problem wrong.

  6. #4
  7. Uguessus is offline Junior Member Pro Subscriber
    Join Date
    Dec 2019
    Location
    Signal Hill, CA
    Posts
    5
    Reputation
    You are right. I made a big mistake on where I should add or deduct the 67deg, 292Deg is right.

  8. #5
  9. Kalbi_Rob's Avatar
    Kalbi_Rob is offline Experienced Member Pro Subscriber
    Join Date
    Feb 2018
    Location
    Jacksonville, NC
    Posts
    290
    Reputation
    Quote Originally Posted by Uguessus View Post
    You are right. I made a big mistake on where I should add or deduct the 67deg, 292Deg is right.
    Always make a visual verification that you are in the right quadrant using the (X,Y) as a basis for your final answer.

  10. #6
  11. Uguessus is offline Junior Member Pro Subscriber
    Join Date
    Dec 2019
    Location
    Signal Hill, CA
    Posts
    5
    Reputation
    Quote Originally Posted by Kalbi_Rob View Post
    Always make a visual verification that you are in the right quadrant using the (X,Y) as a basis for your final answer.
    That's a good point. Thanks.

  12. #7
  13. Join Date
    Apr 2021
    Posts
    32
    Reputation

    Update Question Please

    Any way the moderators may be able to update this question to the correct answer? I also got it marked wrong, and came up with the same answer deemed correct in this forum topic.

  14. #8
  15. Join Date
    Apr 2010
    Location
    United States
    Posts
    558
    Reputation
    Quote Originally Posted by bob152637485 View Post
    Any way the moderators may be able to update this question to the correct answer? I also got it marked wrong, and came up with the same answer deemed correct in this forum topic.
    Thanks for reporting, someone will take a look.

Subscribe

Share this thread

Tags for this Thread

Follow us


Explore TestGuy


NETA Certification Training


NICET Electrical Power Testing


Help and Support




You are viewing the archives. Enjoy new features and join the conversation at wiki.testguy.net