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!

Circular motion

  1. Feb 5, 2004 #1
    The question is :
    A car travel in a flat circle of radius R. At a certain instant the velocity of the car is 18 m/s west and the total acceleration of the car is 2 m/s2 at 46 degrees north of west. What is R?

    I simply used a = v2/R and obtained 162 m. I suspected the question should be more complicated than I thought. Can anyone help. Thanks.
  2. jcsd
  3. Feb 5, 2004 #2
    The formula u applied is for an so u have to take the component which is in the direction of radius or it shoul be radial component of acceleration. and velocity should be the tangential velocity
    Last edited: Feb 5, 2004
  4. Feb 5, 2004 #3
    thanks, maybe more info needed

    I took cos(46) of 2 m/s2 and used for the formula. It's not the correct answer. Do I need to figure out the linear speed? (apparently it is not 18 m/s)?
    Thanks alot.
  5. Feb 5, 2004 #4

    Doc Al

    User Avatar

    Staff: Mentor

    Re: thanks, maybe more info needed

    The linear speed is 18 m/s, nothing wrong with that.

    Draw a picture of what's happening and you will see that you took the component of the acceleration incorrectly.
  6. Feb 5, 2004 #5
    should be sin instead of cos

    I guess I've mistaken the direction 46 degrees north of west as west of north. I have just tried again and it worked. Thanks alot.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Circular motion
  1. Circular motion (Replies: 4)

  2. Circular Motion (Replies: 4)

  3. Circular motion (Replies: 8)