Principle of Flights.

Newton's Law of Motion : 

First Law: 

Law of Inertia: A body at rest tends to remain in rest and body in motions tends to remain in motion in  a straight line at a constant velocity unless acted upon by some unbalanced force. 

F=ma

F=Force, m= mass, a = acceleration

Second Law: 

The Law of Accelerations: A force(F) required to produce change in motion of a body is directly proportional to its mass(m) and the rate of change of velocity or acceleration(a). 

a=F/m

Third Law: 

Action and Reaction: For every action there is equal and opposite reactions. 

Bernoulli's Principle:

The principle was first derived by the Swiss mathematician Daniel Bernoulli. It gives interrelationship between pressure and velocity in a moving fluid (liquid or gas). 

It states that energy is conserved in a moving fluid and the pressure decreases as the speed of the fluid increases. Since there is no addition or subtraction of energy in closed system, the total energy in closed system,the total energy of airflow remains constant throughout the length of the stream tube. 

Venturi -Tube:

The venturi tube is specially shaped tube with a large opening at the front and the rear end with  a restrict or between them. Within a venturi tube ,pressure is decreased to accelerate the speed of the airflow. 

The curved upper surface of a wing could be taken as bottom half of the venturi tube. Airflow over the wing at upper surface air accelerates, the result is a decrease in pressure on the upper surface of the wing that results as one of the source of the "lift".