One plane is flying with a circular path (B) and the other with a straight line path(A). We are given the velocity of both planes and the radius of the circular path. What information is still necessary to write the vector expression for the velocity of A as observed by B?
The equation I am using is VA=VB+(VA/B)rel+omegaxrA/B
3 comments:
To find the desired velocity of A as seen by an observed on B rewrite the equation that you presented in the following form:
(VA/B)rel = VA - VB-omega x rA/B
As you stated, you know vA, vB and rA/B. The only other quantity that you need is the omega vector for the observer on B (that is, the angular velocity vector of aircraft B). Please see my comment posted on the original post entitled "Homework Hint: 5/173" for help on this (to find post and comment, click on the Post Label "Hwk hints: Chapter 5" shown in the box on the right side of the blog page).
Let us know if this does not answer your question.
When I solved this problem, I ended up with -254.56i -1000-something j. I can't figure out where I went wrong because I used the same equation as cmk wrote in his post and found omega using vB/rB/C. My final equation was -360cos(theta)i - 360sin(theta)j - 480j - (-53.3k x -5i) = vrel. Any ideas on why I got the wrong answer? Thanks.
I see a couple things that you need to check.
* The vector rA/B represents the vector FROM B TO A = 5*i. It looks like you used the vector FROM A TO B = -5*i in your solution.
* The answer is given in ft/sec whereas the known information on the speeds and a distances are in mph and miles, respectively. You should convert everything to ft/sec and ft.
Let us know if this does not solve your problems.
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