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!

What are the velocity & position of an object as function of time?

  1. Feb 17, 2015 #1
    1. The problem statement, all variables and given/known data
    A motorboat is moving across a lake at a speed vo when its moot suddenly freezes up and stops. The boat then slows down under the frictional force fR = -bv (a) What are the velocity and position of the boat as a function of time? (b) If the boat slows down from 4.0 to 1.0 m/s in 10s how far does it travel before stopping?

    2. Relevant equations
    fr=-bv

    3. The attempt at a solution
    v=v0 e-b/m *t
    x=x0+ v0m/b (1-e -b/m *t)
     
  2. jcsd
  3. Feb 17, 2015 #2

    Nathanael

    User Avatar
    Homework Helper

    Now use the information from part (b) to find the constant b/m
     
  4. Feb 17, 2015 #3
    how can i find b/m??
     
  5. Feb 17, 2015 #4

    Nathanael

    User Avatar
    Homework Helper

    Put the given information into equations:
    v0e(-b/m)T = 4 m/s
    v0e(-b/m)(T+10) = 1 m/s
    Then you can find how long it takes to stop (which will depend on v0)
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted