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Homework Help: A Man In a Speed Boat Top Speed 15m/s

  1. May 6, 2012 #1
    1. A man in a speed boat, top speed, 15m/s, is crossing a river, 1000m wide, flowing East at 2m/s. The man steers the boat so as to reach a point 150m upstream on the opposite bank. What angle, WthetaN should he steer at? How long does the crossing take?

    2. (Velocityx-2)(T)=-150 Velocity(T)=1000



    3. (-15cosθ-2)T=150 15sinθ(T)=1000

    T=1000/15sinθ
     
  2. jcsd
  3. May 6, 2012 #2
    Just use trig to solve for the angle. Split it into vectors or draw a triangle. You know the river flows 2m/s East and you have to travel 15m/s in such an angle upstream so that you end up at the same point on the opposite side of the river.

    Use trig to find that angle.

    Then to solve for the time, solve for the hypotenuse of the triangle with relation to distance.

    Then time=Distance/Velocity
     
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