Fluids mechanics is a branch of mechanics that is concerned with properties of gases and liquids. Mechanics is important as all physical activities involves fluid environments, be it air, water or a combination of both.
The type of fluid environment we experience impacts on performance.
The ability to maintain a stationary on the surface of the water- varies from he on person to another. Our body floats on water when forces created by its weight are matched equally or better by the buoyant force of water. For an object to float it needs to displace an amount of water that weighs more than itself. Body density, or its mass per unit volume, also impacts on the ability to float. Density is an expression of how tightly a body’s matter is enclosed within itself.
Centre of buoyancy
If our average total body density is higher than that of water, we sink but this does not happen uniformly. Every floating object has a centre of gravity and centre of buoyancy. We saw on page 223 that the centre of gravity is the point around which the body’s weight is equally balanced in all directions. The centre of buoyancy is the centre of gravity of the fluid displaced by a floating object. Around this point, all the buoyancy forces are balanced
When a body or object moves, whether it be in air or water, it exerts a force and simultaneously encounters a resisting force from that medium.In sporting competitions such as swimming and athletics, drag and lift forces are constantly responding to the object or body’s thrust. There are many types of forces exerted by fluids that resist an implement or body trying to move through it. At the same time, technological improve- ments have enabled us to better use the specific fluid to decrease resistance; for example, better configuration of the dimples on a golf ball can improve its flight performance. Drag is the force that opposes the forward motion of a body or object, reducing its...
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