# Fluid Mechanics

Fluid mechanics or fluid dynamics comes into sport a lot and covers air resistance, drag, projectiles, spin on balls and Bernoulli principle and lift force.

Air resistance is a frictional force which occurs when air passes over the surface of a body. This frictional force is not just limited to air though and it applies in fluids, usually water in a sporting situation. Air resistance, drag and fluid resistance mean the same thing.

The Bernoulli principle explains why aeroplanes fly and racing cars stick to the ground going round corners when they really shouldn't. It is to do with lift force and downforce created when air flows over an aerofoil.

The Dutch-Swiss mathematician Daniel Bernoulli discovered that where there is an increase in the velocity of a fluid there is a decrease in the pressure. This is known as the Bernoulli principle.

An aeroplane wing works by splitting the air and sending part of the air over the top curved surface and part below the wing along the flat surface. The air that goes over the curved surface

A projectile is any body which is thrown or jumped into the air. Once it has left the ground it will follow a flight path called a parabola until it once more comes back down to earth. This applies to balls, javelins, discus, long jumpers, high jumpers and horses show jumping. As far as we know there is no escaping the effects of gravity.

Spin is created by applying a force with is off centre to the object being thrown (or kicked) at the point of release. The effects of spin are important in all ball sports and throwing events. The Magnus effect explains why the paths of balls deviate from normal flight path.