Calculating Sailboat Relative Motion with Equations and Conversions

[nysnacc]

Homework Statement

Homework Equations

v_theta = r * theta_dot
1 knot = 1852 m

The Attempt at a Solution

v_0 = 6 * (1852m/h) * (1/3600 h/s) = 3.087 m/s

 

[tech99]

It looks as if the first picture is telling us that the apparent wind is from the W and has a zero N-S component. So the actual wind must have a component equal and opposite to the boat speed, 6 kt blowing from the S.
In the second picture, the tell tale is responding to 6 kt actual wind from the S, and is feeling 3 kt apparent wind from ahead (6 cos 60). So the
6 kt wind created by the boat's motion is being reduced by an actual wind of 3 kt from the W.
Combining these two pieces of information, the actual wind has a component of 6 kt from the S and 3 kt from the W. So a triangle of velocities will give you the answers.