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!

Relative and circular motion

  1. Jan 22, 2013 #1
    You are traveling on an airplane. The velocity of the plane with respect to the air is 120.0 m/s due east. The velocity of the air with respect to the ground is 43.0 m/s at an angle of 30° west of due north.

    1.What is the speed of the plane with respect to the ground?

    I got 82.76 by doing 120-43(cos30)

    but apparently it was wrong the feedback i got was It looks like you incorrectly calculated the planes velocity with respect to the ground in the east direction. Be careful when you calculate the east-west component of the wind's velocity. Also don't forget to include the winds north-south component to get the total speed of the plane with respect to the ground.
     
  2. jcsd
  3. Jan 22, 2013 #2

    Simon Bridge

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    Very good - did you have a question?
     
  4. Jan 22, 2013 #3
    ya thats apparently wrong how do I get the correct solution
     
  5. Jan 22, 2013 #4

    Simon Bridge

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    Well, your answer does not have a direction or any units and you did not supply any reasoning.

    The advise you have is that you made a mistake in your reasoning.
    Go back over it again and consider - what does the wind do with the plane?
    Perhaps if you drew a picture
    - which direction is the "43cos(30)" part pointing in?
    - which direction is the "120" part pointing in
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook