Studied by 24 people
friction
a force between 2 contacting objects that acts parallel to the interface and in opposition to the relative motion
value of friction
f=CoF×reaction force
dynamic friction
friction of a moving object
static friction
friction of a stationary object
coefficient of friction
the value that objects have depends on how “sticky“ they are. For instance ice has a lower CoF than rubber. ratio of frictional force to gravitational force
coefficient of static friction
is a measure of the force required to initiate the movement of an object at rest relative to another surface.
coefficient of dynamic friction
reduces the force required to keep an object moving
magnitude of CoF
depends on the interaction of 2 surfaces in contact. The greater the contact, the greater the CoF. Usually between 0 to 1, but can be greater than 1. This means that it would take more force to slide something than picking it up
friction in sports positives
friction provides grip and traction, which are crucial for stability and control in many sports.
friction in sports negatives
Exessive friction can lead to loss of energy, decrease in speed, and increase wear and tear equipment and surface
Maximizing friction
Wax on skies, rubber on wheels, skates on ice, golf gloves.
minimizing friction
aerodynamics of equipment.
safety and friction
prevent slips and falls, some surfaces can cause injuries in knees and ankles due to exess friction
drag
the force acting to oppose the motion of an object through fluid medium like water/air. The coefficient of drag increases as your velocity increase
form drag
reaction of fluid when a body pushes against it. By streamlining the body and minimizing the surface area facing the direction of the motion, this type of drag is reduced.
surface drag
outer surface of body catches a layer of neighbouring fluid as it moves. Can be minimized by changing the surface to reduce the interaction between surface and fluid.
wave drag
caused by the displacement of fluid (usually water), as the body moves along the surface. Wave drag can be reduced by avoiding motion at the interface between air and water.
factors influencing drag
shape/size of the object, density of the fluid, velocity of the moving body, surface area of the object, equipment, viscosity.
Outline different types of drag and ways they can be reduced in swimming. [6]
Surface drag:
outer surface of body catches a layer of neighbouring fluid as it moves
reduced by creating smooth surface / shaving / shark suit
Form drag:
reaction of fluid when a body pushes against it
proficient / streamlined swimming technique reducing turbulence
Wave drag:
caused by the displacement of fluid (usually water), as the body moves along the surface
swimming underwater for as long as possible
wave-less pools designed to reduce wave drag
Analyse factors that decrease drag for a road cyclist. [5]
a tucked body position decreases surface area/size while cycling decreases drag;
decreased opposing wind decreases drag;
clothing such as tight apparel will decrease drag;
equipment for cycling such as appropriately designed/aerodynamic helmet and bicycle will decrease drag;
avoidance of turbulent air/drafting/being behind the athlete in front decreases drag;
shaving/waxing skin has a positive effect on reducing drag;
lower speed decreases drag
Outline how drag can be changed to maximize performance. [4]
change the shape/texture of the equipment to reduce surface drag
reduce surface area in contact to reduce form drag
decrease the density of the fluid can decrease wave drag
A smooth surface can allow the fluid to flow more easily, reducing drag.
Discuss factors that can affect friction in sport. [4]
Roughness/smoothness of the surface
shape or design of the object/equipment
Sliding surface’s state of matter (solid/fluid)
Temperature
Note 
Flashcard (48)