1. A sailboat can be propelled into the wind by a maneuver called beating to windward. Beating
requires the sailboat to travel in a zigzag pattern at an angle to the wind that is greater than the
no-go zone, which is shaded red in (Figure 1). When a sailboat is just outside the no-go zone
(boats B in the figure) the wind exerts a force F on the sail that has a component in the direction
of motion v Similar comments apply to boats C. The work done by the wind on the sail is W =
Fdcose and because u = d/t, the propulsion power P = W/t delivered to the sailboat is Fucos
where ? is the angle between the sail force and the direction of motion.
Solution
A) Less than
B) The propulsion power delivered, P = F.v
= F*v*cos(theta)
= 860*13*cos(78)
= 2324 W or J/s
C) The propulsion power delivered, P = F.v
= F*v*cos(theta)
= 860*13*cos(55)
= 6412 W or J/s