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Homework Help: Calculate the joggers average velocity

  1. Oct 4, 2006 #1
    A canoeist wants to travel straight across a river that is 0.10 km wide. However, there is a strong current moving downstream with a velocity of 3.0km/h. The canoeist can maintain a velocity realitive to the water of 4.0km/h.
    a) In what diretion should the canoeist head to arrive at a position on the other shore directly opposite to his starting position?
    b) How Long will the trip take him?
    AND
    A jogger runs 15km(N 35 degrees E) and then runs 7.5 km (N 25 degrees W) It takes a total of 2.0 hours to run,
    a)determine the displacement of the jogger
    b)calculate the joggers average velocity
    (I have to break this one into x and y components but I just cant seem to get it right).
     
  2. jcsd
  3. Oct 4, 2006 #2

    Office_Shredder

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    For the canoist, call x the axis across the river, and y the axis going parallel to the river. What must be the y component of the canoe? How can you then solve for the x component?

    For b, what are the standard trig formulae for x and y components?
     
  4. Oct 4, 2006 #3
    First one:
    c²=a²+b²
    4²=3²+b²
    16-9=b²
    b=2.65

    Tan= opp/adj
    tan=3/4
    =o.75*tan-1
    =37 degrees
    answer is suppose to be 41

    Second one:
    x components:12.29+(-3.17)=9.12
    y components=8.60+6.79=15.39
    83.1744+236.8521=c²
    320.0265=c²
    c=18

    answer is suppose to be 2.0*10¹ km(N 16 degrees east)
     
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