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2. The motions of the performer and of the equipment being used take place in a fluid environment 2

3. 1. Flotation, 2. Relative Motion & 3. Fluid Resistance 3

4. Example: Swimmer in water Swimmer is subject to two vertical forces – her weight and the buoyant force Buoyant force = result of all the vertical forces exerted on her by the water 4

5. Question: When will the swimmer float? Answer: If the buoyant force is equal to the weight of the swimmer If the buoyant force is less than the weight, swimmer sinks 5

6. Floating or sinking depends on two factors: 1. swimmer’s weight (mass) and 2. volume of swimmer’s body In other words: Density Density = Mass/Volume 6

7. The density of the human body (and thus whether it will float or not) depends on: 1. amount of bones 2. muscle 3. fat 4. other tissue of which body is composed 7

8. The point or centre of volume of the submerged part of the body is known as the = centre of buoyancy 8

9. Question: What does Relative Motion means? Answer: The motion (or movement) of one person to another person looks the same, no matter which one of the two is moving Similar with motion in fluid environment 9

10. Question: What is Air Resistance? Answer: The force that the air exerts on a moving object Question: What is Fluid Resistance? Answer: Any force that oppose the relative motion of an object through fluid 10

11. Question: What is the Drag? Answer: The component of air resistance that acts in the direction of the opposing flow of air Question: What is the lift? Answer: The force that serves to “lift” the object that moves through the air 11

12. Lift 12 A Javelin Being thrown Relative Flow

13. Question: What is surface drag? Answer: Surface drag slows the forward motion of an object moving in the air Question: What is form drag? Answer: Form drag is due to an imbalance in the resultant forces acting on the front and rear halves of an object moving in the air 13

14. Question: What is the Magnus effect? Answer: The influence that rotation has on the path followed by an object in the air 14

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