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 velocity question

  1. Sep 17, 2015 #1
    1. The problem statement, all variables and given/known data

    A car makes a trip due north for three-fourths of the time and due south one-fourth of the time. The average northward velocity has a magnitude of 27 m/s, and the average southward velocity has a magnitude of 17 m/s. What is the average velocity (magnitude and direction) for the entire trip?

    2. Relevant equations

    ##\displaystyle v_{avg} = \frac{x}{t}##

    3. The attempt at a solution

    ##\displaystyle v_{avg} = \frac{x}{t} = \frac{v_1t_1 + v_2t_2}{t} = \frac{v_1(\frac{3}{4}t) + v_2(\frac{1}{4}t)}{t} = \frac{3}{4}v_1 + \frac{1}{4}v_2 = \frac{3}{4}27 + \frac{1}{4}(-17) = +16~m/s##

    Is this the correct answer for the average velocity over the whole trip? If not, what am I doing wrong?
    Last edited: Sep 17, 2015
  2. jcsd
  3. Sep 17, 2015 #2


    User Avatar
    Science Advisor

    Is the southward velocity 7 or 17?
  4. Sep 17, 2015 #3
    Oops, it's 17 m/s. I fixed it.
  5. Sep 17, 2015 #4


    User Avatar
    Science Advisor

    In that case, your work looks correct.

    Edit: The question asks for magnitude and direction rather than a signed result.
  6. Sep 17, 2015 #5
    Alright, I'll take that into account. Thanks!
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted

Similar Discussions: Simple velocity question
  1. Simple Velocity question (Replies: 11)

  2. Simple velocity question (Replies: 11)