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Homework Help: Relative Velocity

  1. Feb 9, 2008 #1
    1. The problem statement, all variables and given/known data

    A Coast Guard cutter detects an unidentified ship at a distance of 23.1 km in the direction 16.8° east of north. The ship is traveling at 24.7 km/h on a course at 43.1° east of north. The Coast Guard wishes to send a speedboat to intercept the vessel and investigate it. If the speedboat travels 48.9 km/h, in what direction should it head? Express the direction as a compass bearing with respect to due north.
    _____degrees east of north

    2. Relevant equations

    im not sure if there are any specific ones but i was using triangle theorems to try and figure it out

    3. The attempt at a solution

    ok so i pictured the whole thing as a triangle. one side 23.1 because thats where the ship was detected, another side 24.7, and the final side 48.9. i tried solving for an angle but i think i'm not really getting what the question is asking
  2. jcsd
  3. Feb 9, 2008 #2
    hmmm, im certainly a noob here, but you cant evaluate this as a set triangle. The triangle will be dependent on the velocities of the 2 boats. I think you may have to do some vector addition here and possibly use an equation that involves the final coordinate x where the 2 boats will be equal.
    Thats my best advice.
    Good luck.

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