1. 13 Fluids density pressure in a fluid buoyancy and archimedes’ principle Fluids in motion Hk: 21, 31, 33, 41, 43, 55.

2. Density  = mass/volume SI Unit: kg/m 3 common unit: g/cm 3 1,000 kg/m 3 = 1 g/cm 3

3. Pressure, p p = force/area Unit: pascal, Pa 1 Pa = 1N/m 2. Example: 100N applied to 0.25m 2. Pressure = 100/0.25 = 400N/m 2.

4. Pascal’s Principle

5. Bulk Modulus B = -  P/(  V/V) compressibility = 1/B liquids have large B gasses have smaller B

6. Depth and Fluid Pressure P = P o +  gd P is the pressure at depth d. P o is the pressure at the fluid surface  is the fluid density Example: increase in pressure at a depth of 1m in water = (1,000)(9.8)(1.0) Pa

7. Buoyancy and Archimedes’ Principle

8. 8

9. 9 At same velocity: lower height fluid is at greater pressure At same height: faster moving fluid = less pressure

10. Summary Density = mass/volume pressure in a fluid varies with depth Buoyant force = weight of displaced fluid Fluids in motion /

11. Gauge Pressure is Differential Pressure

12. Barometer

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