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Homework Help: Does wind speed matter?

  1. Feb 21, 2010 #1
    1. The problem statement, all variables and given/known data
    A car leaves point A and drives at 80.0 km/h [E] for 1.50h. It then heads north at 60.0 km/h for 1.00h and finally [30o W of N] at 100.0 km/h for 0.50g arriving at point B.

    a) Determine the displacement of point B from point A.
    b) A plane flies directly from point A to point B, leaving 2.00h after the car has departed from A. It arrives at point B at the same time the car arrives. There is a wind blowing at 60.0km/h due south for the entire trip. What is the airplane's airspeed?
    c) What direction must the plane head in order to arrive at point B?
    d) How long would the plane's trip be if there was no wind?

    2. Relevant equations

    All the ones dealing with motion.

    3. The attempt at a solution

    I got the answer for a. It is 114 km. How would I do b c and d? I have no idea where to begin.
  2. jcsd
  3. Feb 21, 2010 #2


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    Can you be more specific? Then we can point out the right starting point.
  4. Feb 21, 2010 #3
    I just used SOH CAH TOA and v = d/t equations because there is no acceleration or anything. It is just vectors and diagrams. The wind speed got me confused because we did not learn about it.
  5. Feb 21, 2010 #4


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    If you understand vector addition, then you can handle wind speed without problems.

    vPG = velocity vector of plane relative to the ground
    vAG = velocity vector of air (or wind) relative to the ground
    vPA = velocity vector of plane relative to the air


    vPG = vAG + vPA
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