Sailing theory

It seems obvious how a sailboat sails downwind: It is pushed along by the wind in its sails. Less obvious is how it can sail upwind or how some sailboats can sail faster than the wind. Let us see how it can be.
Sir Isaac Newton formulated three basic laws that pertain to the motions and accelerations of all objects.
Let us have a look at the third law:
For any force exerted on an object, an equal but opposite force must be exerted by that object onto whatever exerted the force.
A direct consequence of this law is the conservation of momentum (Momentum equals mass times velocity). The conservation of momentum tells us that if the velocity of one thing is somehow changed (in either magnitude or direction) that the velocity of something else must also change accordingly.

Moreover, a large change in velocity of a light object can be balanced by a small change in velocity of a massive object. This is, of course, how a sailboat sails. Because of its large sail area, a sailboat can change the velocity of a huge amount of air in a small amount of direction or speed.
The change of velocity that the sailboat imparts to the air hitting her sails is mainly a change in the direction in which the air is moving. So a sailboat can experience a large driving force even when she is sailing against the wind.
In the real world, there are two forces. One is the wind pushing on the sail when it is changing direction. The air traveling over the leeward surface of the cambered sail creates the second force. It has to travel a longer way to reach the end of the sail (the leech), and as a consequence goes faster. This is causing a pressure differential in accordance with Bernoulli’s principle. (More speed gives less pressure and less speed gives more pressure).
So a sailboat can sail upwind with the addition of these two forces. But remember that the force created by the depression is four times bigger that the one created by pushing the air sideways.

A fluid flow exerts a force upon an object in a direction perpendicular to the uninterrupted flow of that fluid. As a result, a lift is generated. But there is also creation of a drag that is a force acting in the direction of the fluid.Because lift and drag are defined as being perpendicular to one another, any force acting on a sail can, using trigonometry, be divided into a lift component and a drag component. By separating the force into these two components, we can study the relationships between lift, drag, the shape of the sail, and the angle between the sail and the airflow( AOA or Angle Of

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