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!

Simple,quick relative velocity question?

  1. Sep 9, 2009 #1
    Hello I'll make it quick

    Boat is travelling at 10m/s the sea is travelling at 5m/s. What is the speed of the boat relative to the sea and why?

    Through vectors I worked it out to be 10m/s(not sure) but shouldn't it be five because if a person is standing in the sea and sees the boat it would be travelling at 5m/s.

    The ship relative to the ground is 15m/s right.

    Thank you!!
     
  2. jcsd
  3. Sep 9, 2009 #2

    rock.freak667

    User Avatar
    Homework Helper

    B=boat
    S=Sea
    G=ground.

    B/S= Boat relative to Sea


    I assume if there is a diagram it looks like this


    --------> boat
    ----> sea

    [tex]\vec{v}_{B/S}=\vec{v}_B-\vec{v}_S = 10-5=5 m/s[/tex]


    So the boat 'feels' as if it is traveling at 5m/s instead of 10m/s
     
  4. Sep 10, 2009 #3
    Thank you for your help. Isn't it 15m/s-10m/s. That is where my confusion lies. Isn't the boat relative to the ground 15m/s(someone in the shore would feel the boat travelling at 15m/s). When you are in the boat do you feel the resultant velocity or the actual velocity.
     
  5. Sep 10, 2009 #4

    Doc Al

    User Avatar

    Staff: Mentor

    With respect to what? The water or the ground? And in what direction?
    Presumably with respect to the ground.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Simple,quick relative velocity question?
Loading...