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: Position, velocity, and acceleration yes or no question

  1. Jan 31, 2010 #1
    1. The problem statement, all variables and given/known data

    A ball is lodged in a hole in the floor near the outside edge of a merry-go-round that is turning at constant speed. assuming that the position is measured from an origin at the center of the merry-go-round do the magnitudes of the position, velocity, and acceleration vectors change with time?

    2. Relevant equations

    N/A

    3. The attempt at a solution

    I believe the answer is yes because at any given time the position will be different and at any given time the velocity and acceleration will be different because they change with direction since they are vectors.

    Am i correct about this?

    Thank you
     
  2. jcsd
  3. Jan 31, 2010 #2
    now i am rethinking this because it says magnitude so is it maybe no because the magnitude of the position will be the same?
     
  4. Jan 31, 2010 #3

    PhanthomJay

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Yes, No is correct, now you got it right.
     
  5. Jan 31, 2010 #4
    ok thank you :)
     
  6. Jan 31, 2010 #5
    just to make sure i am understanding this correctly

    would none of the magnitudes change with time because the magnitude of a vector changes with time only if the length changes with time and the length of this never changes correct?
     
  7. Jan 31, 2010 #6
    bump^^^^

    anyone know if i have the right theory behind this?

    would none of the magnitudes change with time because the magnitude of a vector changes with time only if the length changes with time and the length of this never changes correct?

    thanks :)
     
  8. Feb 1, 2010 #7

    PhanthomJay

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    The position, velocity, and acceleration vectors all change with time, because their direction changes with time. Their magnitudes , however, stay constant; as you noted, the length of the position vector (the distance between the ball and the center of the carousel) does not change with time (it stays the same no matter where the ball is as it rotates along with the carousel). The magnitude of the velocity vector and the magnitude of the acceleration vector also do not change with time.......why?
     
  9. Feb 1, 2010 #8
    Does the magnitude of velocity vector and the magnitude of the acceleration vector not change with time because the speed of the carousel is constant?
     
  10. Feb 1, 2010 #9

    PhanthomJay

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    That is correct.
     
  11. Feb 1, 2010 #10
    Thank you for all the help and great explanations and other non-math related information.

    I really appreciate the help
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook