1. Limited time only! Sign up for a free 30min personal 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!

Homework Help: More vector help

  1. Sep 20, 2006 #1
    I am stuck on two problems and I keep getting them wrong. Its been a while since I did vectors so I'm a little rusty.

    1. Bob walks 200 m south, then jogs 730 m southwest, then walks 200 m in a direction 27.0 degrees east of north. What is the distance and angle?

    2. A flock of ducks is trying to migrate south for the winter, but they keep being blown off course by a wind blowing from the west at 6.0m/s. A wise elder duck finally realizes that the solution is to fly at an angle to the wind. If the ducks can fly at 8.0m/s relative to the air, what direction should they head in order to move directly south?

    I know these are probably simple, but I'm banging my head on these two. For problem 1, I tried graphically to resolve the vectors using tip to tail but my apporach. Promlem 2 if the wind is blowing from the west so its 6m/s east?
  2. jcsd
  3. Sep 20, 2006 #2


    User Avatar
    Homework Helper

    Yes, draw the vectors and everything should be prefectly clear.

    [tex]\vec{v}_{ducks, total}=\vec{v}_{wind}+\vec{v}_{ducks,relative to wind}[/tex]. The wind vector is known, as is the direction of the final velocity vector of the ducks. Just use the vector equation and the known magnitudes. Solve graphically. :smile:
  4. Sep 20, 2006 #3
    I'm getting a rounding or sig fig error on #1. For the distance I got 710.7 so 711?
  5. Sep 20, 2006 #4


    User Avatar
    Homework Helper

    I didn't notice this earlier, but you did not specify in what direction he walks 'east of north'. You can go 'up' or 'down' from there, and depending on that, you get two solutions; one around 800 m, and the other around 1000 m.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Similar Threads for More vector help Date
Need MORE help with vectors by tomorrow. Oct 27, 2007
More vector help (subtraction) Sep 16, 2007
Vectors and more vectors Sep 9, 2007
One more Vector problem and we are good to go Sep 25, 2006
One more on vectors Aug 29, 2006