IB SEHS HL Topic 10. Friction and Drag

Terms in this set (7)

surface drag
as a body moves through a fluid, its outer surface catches a layer of the fluid nearby, slowing it down compared to the fluid further away and so causing drag. This can be minimised by changing the surface to reduce the interaction between surface and fluid.
it is caused when air or water molecules are in direct contact with a specific area, in which the nature of the surface directly affects the drag.
This is useful in sports, specifically swimming, because it helps them increase the speed to the max which they can (e.g swim caps, speedo shorts and shaving hair to increase smoothness).
form drag
As a body pushes against a fluid, the fluid pushes back (action and reaction). By streamlining the body and minimising the surface area facing the direction of the motion, this type of drag is reduced.
Adjustment of positioning to increase aerodynamics
It can change the way a person/object moves to allow for better performance E.g - cyclists adopting a low profile position, Sprinting form (running)
wave drag
When a body moves along the surface fluid (usually water) some fluid displaced to form a wave. These waves cause additional forces that oppose motion. Wave drag can be reduced by avoiding motion at the interface between air and water.
Wave drag develops when a swimmer is moving quickly across the top of a body of water, creating waves. These waves cause imbalances in pressure on the body and can limit how fast a swimmer can move.
Wave drag should be decreased as it leads to a decrease in speed of swimmers for example. (stay underwater longer to reduce wave drag)
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