1. Not finding help here? Sign up for a free 30min 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!

Word problem

  1. Oct 7, 2008 #1
    1. The problem statement, all variables and given/known data
    Frank wants to cross a 2.5 km wide river which flows from east to west in a straight path at a rate of 5 km/hr. On the south shore of the river Frank hops in his boat which has a still water speed of 10 km/hr. Frank points the nose of his boat directly north throughout the crossing. How far downstream from his starting point does Frank reach the north shore. How long was the trip

    2. Relevant equations

    3. The attempt at a solution
    I drew a triangle and determined his speed to be 11.18 km/hr
    How do i now figure out a triangle that relates to distance when I was dealing with rate?
    If the hypotenuse of the rt triangle that I drew was the 11.18 rate of the boat across the river, I can't figure out how to determine the distance down river that he ends up.
  2. jcsd
  3. Oct 7, 2008 #2
    Okay, I tried it again. Please tell me if I am totally off.
    I had the original right triangle with 11.18 as the hypoteneuse.
    I figured the angle there to be 26.5°
    Then I said 2.5/cos 26.5°=2.79
    Once I had that, Sqrt(2.79^2-2.5^2)=1.24 which is the distance downstream.
    Time would be 2.79*11.18=31.192
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Word problem
  1. Word Problem (Replies: 3)

  2. A word problem (Replies: 3)

  3. Word problem. (Replies: 11)

  4. Word problem (Replies: 6)

  5. Word problem (Replies: 3)