find the trajectory of a boat that moves in a river

1. The problem statement, all variables and given/known data
A boat part from the point P of the bank of a river, with width D, and that flows with a constant velocity VR, and moves with a constant velocity VB, directed towars a point Q, located on the other side of the river directly in front of P. If r is the instantaneous distance of the boat respect to Q and θ is the instantaneous angle between r and PQ, show that the trajectory of the boat is determined by:

r=Dsecθ/(secθ+tanθ)VB/VR

2. Relevant equations

3. The attempt at a solution
I am completely lost in this problem; I to put the instantaneous distance of the boat r as a vector and a took Q as my origin r = cos(90-θ)i+sen(90-θ)j but then i dont know what else to do; I would appreciate your help a lot

http://ift.tt/1eTIRSj

Leave a comment

Your email address will not be published.


*


Show Buttons
Hide Buttons