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: How long does it Take to Catch

  1. Sep 25, 2012 #1
    "Assume that the Deschutes River has straight and parallel banks and that the current
    is 0.75 m/s. Drifting down the river, you fall out of your boat and immediately grab
    a piling of the Warm Springs Bridge. You hold on for 40 s and then swim after the
    boat with a speed relative to the water of 0.95 m/s. The distance of the boat
    downstream from the bridge when you catch it is..."

    I've solved a similar problem in the past and normally I'd reference that homework, but my teacher has yet to hand that back. If someone could just point me in the right direction (i.e., set it up and tell where to go from there) I'd appreciate it.

    Nevermind! Read post #2
    Last edited: Sep 25, 2012
  2. jcsd
  3. Sep 25, 2012 #2
    Nervermind, just figured this out. I'd delete this thread but don't know how.
  4. Sep 25, 2012 #3
    The easiest way to go about this is to solve for t
    To do this you're going to want two equations, one for the boat, and one for you swimming
    Use the kinematic x = Vot + 1/2at^2 for the equation (no acceleration makes this pretty simple)
    As for the time difference, the time that the boat is traveling before it is caught is just time t correct?
    Well using that, since you wait 40 seconds before chasing the boat, is it not true that the time that you swim is 40 seconds less than the time the boat is floating? Aka t - 40
    From there it's just algebra, then use the time you find to find the displacement of the boat

    EDIT: Whoops, didn't see that post you made. Wish I knew how to delete posts haha
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook