1. Chapter-9 The Behavior of Fluids

2. Outline 1 Pressure, Hydraulics, and Pascal’s Principle 2 Atmospheric Pressure and the Behavior of Gases 3 Archimedes’ Principle 4 Fluids in Motion 5 Bernoulli’s Principle Everyday Phenomenon: Throwing a Curve Ball

3. A steel boat floats, but a piece of metal sinks. Why?

4. Fluids Fluids are materials that can flow, gases and liquids. Air is the most common gas, and moves from place to place as wind. Water is the most familiar liquid.

5. Pressure

6. Tire Pressure People who have fixed a flat tire know something about pressure. In colliding with the inner walls of the tire, the air molecules (blue dots) exert a force on every part of the wall surface.

7. Pressure The pressure P exerted by a fluid is defined as the magnitude F of the force acting perpendicular to a surface divided by the area A over which the force acts: The SI unit for pressure: newton/meter 2 = (N/m 2 ) = pascal (Pa).

8. Area of a square

9. Area of a rectangle Length Width Area = Length x Width.

10. Area of a circle d Area =  r 2, d = diameter = 2r.

11. Pressure acts everywhere

12. Pressure Acts Everywhere

13. Pascal's Principle Any change in the pressure applied to a completely enclosed fluid is transmitted undiminished to all parts of the fluid and the enclosing walls.

14. Hydraulic Jack

15. Car Lift

16. Hydraulic Car Lift

17. E5

18. Atmospheric Pressure Atmospheric pressure at sea level is 1.013 × 10 5 Pa, which is sufficient to crumple a can if the inside air is pumped out.

19. Mercury Barometer At sea level, Height of mercury = h = 76 cm. Atmospheric pressure = 76 cm of Hg. (76 cm = 760 mm = 29.9 inch)

20. Variations in atmospheric pressure

21. Density of air decreases as the altitude increases