The Physics of Sailing

The Physics of Sailing

Sailing downwind When the wind blows into the sails and pushes against them, it moves the boat forward. The wind is faster than the boat so the air is decelerated by the sails. While the sails push backwards against the wind, the wind pushes forward on the sails. Which means you can never sail faster than the wind. According to the laws of force, it is easier to go with the wind pushing on your back. The wind usually pushes you in the direction it is going. Sailing directly upwind Boats can sail at say 40° to the wind and by taking Sailboats can sail in any direction that is greater than 45 degrees with respect to the wind. Initial velocity and final velocity, which are given with respect to the boat. The change of velocity dv is in the direction shown. The acceleration of the air is dv/dt, so the force which is the air that the sails exert in the same direction. Newton's first and second laws: F = ma. The force that the wind exerts on the sails is in the opposite direction. There is also something going on called the Bernoulli effect, which contributes to the force as well. The wind fills the sail into the shape of a wing The sail is held fast at both ends so the wind can't push it out of the way. The wind must change direction to flow parallel to the sail. The taut sail has created a force on the wind that causes it to change direction This is a direction example of Newton's third law that says that there is an equal and opposite force on the sail by the wind Sailboats can move faster than the wind itself When sailing upwind, the relative speed of the wind on the sails is greater than the actual speed of the wind and this relative wind creates a larger force on the sails that can push sailboats faster than the actual wind speed.

Sailing close to the wind

• The shape of the sails is used to generate lift.
• To flow around the sails, the winds direction must change.
• The force is mainly sideways on the boat and it gets more sideways as you get closer to the wind.
• Part of the force is forward which is the desired direction.

Other Forces

• The large area of the keel resists being dragged sideways through water.
• The water applies a force to the boat that increases with greater surface area.
  
  
  
  

Citation:

• "The Physics of Sailing: How Does a Sailboat Move Upwind?" Physics Buzz:. N.p., n.d. Web. 22 Oct. 2016.

Jared Blatt

Mr. Gray

Period G

21 October 2016