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Homework Help: Car Velocity question

  1. Jun 18, 2009 #1
    This is a Question with 3 parts.Any help will be appreciated.Also can you explain what is magnitude of velocity?

    1. Two cars approach each other; both cars are
    moving westward, one at 76 km/h, the other
    at 66 km/h.
    What is the magnitude of the velocity of the
    first car relative to (in the frame of reference
    of) the second car? Answer in units of km/h.

    2. What is the direction of the resultant veloc-
    1. eastward
    2. Unable to determine.
    3. westward

    3. TAfter they pass, how will their relative veloc-
    ity change?
    1. No change.
    2. Less than before.
    3. Unable to determine.
    4. Greater than before.
  2. jcsd
  3. Jun 18, 2009 #2
    Velocity is a vector. Every vector can be described by its magnitude and direction relative to some system of axes.
    A velocity vector of 10 km/h north-west, for instance, would have a magnitude of 10 km/h and its direction would be 45° relative to the east-west axis.
    Last edited: Jun 18, 2009
  4. Jun 18, 2009 #3


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    Homework Helper

    Forget physics. Imagine sitting in the second car and watching the first car, which happens to be faster. What would you see?
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