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: The canoeist crossing a river

  1. Feb 18, 2008 #1
    A canoeist who can paddle 5km/h in still water wishes to cross a 400 m wide river, with 2km/h current. If he steers the canoe perpendicular to the current and wants to get straight across the river how long will it take him to cross the river.

    Which way is right? and why?

    hypotenuse = 5 km/h
    ................| (ignore dots)
    ................| < 2 km/h
    ^ 400 m & 4.58 km/h
    Θ = 22*

    option 1:

    t = 0.4 km / 4.58 km/h

    option 2:
    cosΘ = a / h
    cos 22 = 0.4 km / h
    h = 0.43 km

    now i do t= .43km / 4.58 km/h

    t= 5.63 minutes
    Last edited by a moderator: Feb 18, 2008
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted