vector calculus in mathematics

Question

A boat travels due West with a speed of 30 mph. If there is a 7 mph current at North 30 degree West, find the actual speed and direction of the boat.

1

Answer 1

a=7 α=?

b=30 β=30°

c=over-all speed γ=?

c^2=a^2+b^2-2ab(cosγ)

a/sinα=b/sinβ=c/sinγ=30/sin30=60; 7/sinα; α=asin.116.7; α=6.7°; γ=143.3°

49+900-420(cosγ)=143.3^2

γ=35.857°

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