IB Sports, exercise and health science B.2.2 Fluid Mechanics Key Definitions

Air resistance describes the forces that are in opposition to the relative motion of an object as it passes through the air.

Angle of projection is the angle formed by the initial velocity of a body and the horizontal plane through which the body is thrown.

When fluid velocity increases, pressure decreases, and vice versa. This principle explains how lift is generated in sports.

Buoyancy is the upward force exerted by a fluid (air or water) that opposes the weight of an object submerged in it.

Drag is the resistive force that opposes the motion of an object through a fluid.

External factors such as temperature, humidity, air pressure, wind, water salinity, and altitude that affect the forces acting on objects and athletes during sport performance.

Form Drag is the drag caused by the separation of the boundary layer from a surface and the wake created by that separation

The force that attracts a body towards the centre of the earth, or towards any other physical body having mass.

The height above the ground level, or the height above the point of landing, of the centre of gravity of a projectile immediately before it leaves the ground.

A condition where the body’s core temperature drops below 35°C, impairing normal physiological functions and potentially leading to severe health complications.

Initial velocity is the speed at which a projectile is launched. It has two components:

Lift is the force that acts at a right angle to the direction of motion through the air. Lift is created by differences in air pressure.

The curved path an object follows when it is launched into the air and influenced by gravity and air resistance.

Spin is the total angular momentum, or intrinsic angular momentum, of a body

Surface drag is the resistance that occurs when an object moves through a fluid, such as air or water, due to friction between the object's surface and the fluid.

Wave Drag is a drag force acting on a body that is moving at the interface of two fluids.