SOLUTION: Two docks are directly opposite each other on a southward flowing river. A boat pilot wishes to go in a straight line from the east dock to the west dock in a ferryboat with a crui

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Question 446593: Two docks are directly opposite each other on a southward flowing river. A boat pilot wishes to go in a straight line from the east dock to the west dock in a ferryboat with a cruising speed of 8.0 knots. If the river's current is 2.5 knots, what compass heading should the pilot maintain while crossing the river? What is the actual speed of the boat relative to land?
Answer by Alan3354(69443) About Me  (Show Source):
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Two docks are directly opposite each other on a southward flowing river. A boat pilot wishes to go in a straight line from the east dock to the west dock in a ferryboat with a cruising speed of 8.0 knots. If the river's current is 2.5 knots, what compass heading should the pilot maintain while crossing the river?
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The angle wrt the due west course is arcsin(2.5/8) =~ 18.2 degs
The heading is 288
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What is the actual speed of the boat relative to land?
The speed is 8*cos(18.2) =~ 7.599 knots
It's also sqrt%288%5E2+-+2.5%5E2%29 = same answer