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Homework Help: How far is the hurricane from an island

  1. Sep 25, 2006 #1
    The eye of a hurricane passes over Grand Bahama Island. It is moving in a direction 60.0° north of west with a speed of 41.0km/h. Exactly 3 hours later, the course of the hurricane shifts due north, and its speed slows to 25.0km/h. How far from Grand Bahama is the hurricane 4.50 hours after it passes over the island?

    http://img242.imageshack.us/img242/6613/scan0001iq8.jpg [Broken]

    -I'm really stumped over this question. Like I know I have to make a triangle and use sine, cosine... one of those, but I have no idea where to get started. Mainly because I missed the last 2 days of physics class. Some help would be truly appreciated.
    Last edited by a moderator: May 2, 2017
  2. jcsd
  3. Sep 25, 2006 #2


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    How long does it travel due north?

    Make points A, B, and C as such:

    A: Grand Bahama Island
    B: The location of the hurricane when it shifts directions (three hours after passing over Grand Bahama Island)
    C: The final location of the hurricane

    What two side lengths do you know? What angles do you know?
  4. Sep 25, 2006 #3
    it's travels 1.5 hours due north. and i know the 60.0° which is it's initial direction but tht doesnt tell me the angle inside the triangle. and also i know the 2 sides are 123km and 37.5 km.
  5. Sep 25, 2006 #4
    if u look properly, u'd be able to find the obtuse angle in the triangle, which is the only angle u need to get ur answer.

    if u draw a line parallel to the dotted line, at where the hurricane changes direction, u get to realise an alt angle, dont you?

    from there i think i should be able to find the abutse angle, and then proceed to use the cosine rule to get the distance from the island to the hurricane 4.5 hrs later.

    pls correct me if im wrong.
  6. Sep 25, 2006 #5
    no i think ur right. so cosine of degrees?
  7. Sep 25, 2006 #6
    hmm? are you asking me for a direct answer? look closely.
  8. Sep 25, 2006 #7
    nvm i got the answer
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