# Real-World: Swimming

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1. Coefficient of Drag
*speed up*
2. Area of Drag
*speed up*
3. Fluid Density
*speed up*
4. Relative Velocity
*speed up*
5. Area of Lift
6. Coefficient of Lift
7. Muscle Force
8. Moment Arm
9. Mass
*speed up*
10. Radius of Resistance
11. Application Time of Each Muscle Torque
12. Radius of Rotation
13. Fluid Density
*slow down*

There are two fluid conditions that would change the density of water:

(1) water temperature (warmer water = density reduced)

(2) water type (fresh water = density reduced)
14. Coefficient of Drag
*slow down*

A measure of the surface friction between the water and the surfaces of the swimmer's body.

The coefficient of drag may be INCREASED by making the surface of the swimmer's foot rougher.

-no methods for increasing foot roughness

-swimming shoe that has a surface rougher than the foot's natural surface could be designed

The coefficient of drag may be DECREASED by making the surface of the swimmer's body smoother.

For the swimmer, this is accomplished in 3 ways:

(1) the swimsuit must be made of materials that are extremely smooth

(2) the swimsuit must be tight-fitting

(3) any uncovered areas of the body should have body hair removed
15. Area of Drag
*slow down*

A measure of the area of turbulent water behind the swimmer's foot as the foot moves up and down through the water.

There is one mechanism for increasing the area of turbulent water behind the swimmer's foot: make the area of the foot that collides with the water larger.

The method for making the area of the foot that collides with the water larger is to increase the size of the foot. That can be accomplished by wearing a foot device that increase the size of the foot. Diving flippers area a good example of a foot device that increases the area of drag.
16. Relative Velocity
*slow down*

A measure of the speed and direction of the water that is colliding with your foot or body.

There are two approaches to reducing relative velocity:

(1) swim in bodies of water that have no current (swimming pools/fresh water lakes)

-when you swim with a current, your relative velocity is reduced

(2) use a movement technique called "drafting"

-following swimming experiences a smaller drag force

-less energy expenditure (can lead to finishing swim with a short duration sprint around lead swimmer)
17. Body Density
To increase the buoyant force, the overall body density must be reduced compared to the density of the water.

There are two mechanism that can be used:

(1) remove body components or materials that have densities greater than the density of water

(2) add body components or material that have densities less than the density of water

ALSO:

To reduce body density relative to water density, you would need to lose muscle mass and/or increase fat mass. This would never be a recommendation. Thus, there is nothing you can do to remove or add body components that will decrease your body density.

You could wear swim clothing that has a density less than the density of water. One example is a wetsuit. If thrown in water, a wetsuit will float. This demonstrates that it has a density less than water. Therefore, if you swim wearing a wetsuit, you will decrease your body density relative to water density.
18. Application Time of Each External Force
Decreasing the application time of the only external force that is slowing the body down, the drag force, would be a major mechanism for reducing the magnitude of the internal forces the body must absorb.

Unfortunately, there is nothing that can be done to reduce this application time. If the swimmer is moving, a drag force will oppose the motion and slow the body down.
19. Mass
*slow down*

Theoretically, increasing the mass would be an effective method to reduce how quickly you slow down.

Unfortunately, a larger mass is more difficult to move quickly. There is a mass concept box on the speeding up side of the model; and the interpretation for that box was that the mass must be small if we want to effectively speed the body up.

These two interpretations conflict. However, the logic should be easy to see. We need to get the body moving quickly each time we pull ourselves forward through the water. This requires the mass be as small as we can make it. There is no way to simultaneously increase the mass so that we don't slow down as much.
20. Distance
Unlike running and road cycling, swimming generally is performed following a straight path.

In a pool, you swim down a length of the pool. You turn around and then swim back a length of the pool.

There is no curve. In open water swimming, there is a starting point and ending point. You swim from the start to the end. Again, there are no curves. Thus, the only way to minimize the distance is to swim as straight a line as possible.
 Author: Anonymous ID: 247987 Card Set: Real-World: Swimming Updated: 2013-11-20 04:58:37 Tags: need work Folders: Description: need work Show Answers: