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Homework Help: Position, velocity, and acceleration vectors

  1. Sep 23, 2008 #1
    1. The problem statement, all variables and given/known data

    A motorist drives south at 20m/s for 3min, then turns west and travels at 25m/s for 2min, and finally travels northwest at 30m/s for 1min. For this 6min trip, find:
    a) the total vector displacement
    b) the average speed
    c) average velocity

    let the positive x axis point east

    2. Relevant equations

    Vs = d/delta t
    Vave= delta x/delta t

    3. The attempt at a solution

    i converted the mins to seconds, getting

    south = 3600m
    west = 3000m
    northwest = 1800m

    im getting confused because displacement is not the same as distance so i cant just add all 3 values together

    for average speed i for 8400/6min = 23.3m/s

    and im not sure how to find the change in x for average velocity..

    please help! thank you! =]
  2. jcsd
  3. Sep 23, 2008 #2


    User Avatar
    Homework Helper

    You found the speed. But Velocity is a vector. So is displacement.
    Its magnitude is Displacement divided by the scalar Time.
    So the average for the trip will be the total displacement divided by 360s.
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