1) Several physics principles are involved in sailing, including Newton's laws of motion, Bernoulli's principle, and Newton's third law. 2) Bernoulli's principle states that the pressure of a fluid decreases as its flow speed increases, so the pressure above a sail is lower than below it, creating lift. 3) Newton's third law applies as the wind pushes on the sail and the sail pushes back on the boat with an equal and opposite force, propelling the boat through the water.

1. Sailing
Conceptual Physics
annie cloutier 2012 copyright
Wind Power is the Force
Nweton’s Second Law F = m a
Newton’s Third Law
Action ~ Reaction
Bernoulli’s Principle

2. http://science.kqed.org/quest/video/the-physics-of-sailing/
 Position  Is defined in relation to a
reference point
 Velocity is described by
 Velocity direction and speed of an
object
 ∆ delta means change
 Change in velocity is due
to changes in speed,
direction or both

3. An original idea…

4. Understanding Motion
 Speed  How fast an object is moving
calculate by dividing the distance
covered by time
 Instantaneous speed  The speed at any instant
 Average speed is the total
 Average speed distance covered divided by
the time
 Total distance  Is the average speed times
the travel time

5. NEWTON’S THIRD LAW Action - Reaction
For every action there is an equal and opposite reaction
 When an object is subjected to multiple forces at
once, the result is the cumulative effect of all the
forces
 When forces on an object are balanced, the object
will change its velocity
 When forces are not balanced, no acceleration occurs
 When a body A exerts a force on a body B, B exerts
an equal and opposite force on A

6. Newton’s Third Law
Inversely proportional
 cannonball F/m =a
 Cannon F /m=a

7. Velocity and Acceleration
 Velocity  Acceleration
 Is speed in a given  Is the rate at which the
direction velocity is changing
 Speed is a description  Acceleration can apply
of how fast an object is to decreases as well as
moving increases in speed
 Velocity is how fast  Deceleration is the
and in what direction it decreasing of speed
moves (slam on your brakes)

8. Conservation of Energy
 An unbalances force on an object produces a
change in momentum
 States that the energy can not be created or
destroyed
 Energy can be transferred from one form into
another, but the total amount of energy never
changes.

9. Bernoulli’s Principle

10. Pressure, push or pull is FORCE

11. Henri Coanda Romanian Jet Design scientist 1886-1972 and
Sir Frank Whittle British scientist
http://www.youtube.com/watch?v=EYuNKarb8oY

12. http://web.mit.edu/2.972/www/reports/sail_boat/sail_boat.html
 But you can never sail
directly into the wind

13. Activity :
Bernoulli’s Principle
 5 cm wide x 28 cm long
strip of paper
 Blow across the top of
the paper strip
 Notice the position of
the end of the paper.

14. The end