1. Day 62, Tuesday, 1 December, 2015 Fluid Mechanics Fluids Pressure Pascal’s Principle Archimedes's Principle Pressure at depth

2. Fluids

3. No shape of their own Pressure Pascal's Principle Archimedes's principle Pressure at depth

4. Fluids Fluids have no shape of their own Liquids have no shape but definite volume Gases have no shape and variable volume

5. Density D = M/V ρ = m/vρ (rho) ≡ density

6. Pressure P = F/A Perpendicular to surface

9. Pascal's Principle Blaise Pascal 1623 – 1662, French physician Pressure is transmitted undiminished through a fluid. Shape has no effect. Pressure is transmitted equally to every point in the fluid and to the walls of the container.

10. Pressure depends on the depth, not on the shape

11. Hydraulic Press

12. Archimede's principle Archimedes – Greek scientist 212 B.C. F b = ρVg Density of a fluid is rho or ρ The magnitude of the buoyant force is equal to the weight of the displaced fluid

14. Pressure at depth P = F/A = mg/A d =m/v => m = dv P = dvg/A v =Ah P = dAhg/A P = dhg d = ρ P = ρgh

15. Summary P = F/A Pascal’s principle: Pressure is transmitted undiminished through a fluid. (shape has no effect) Archimedes's principle: Buoyant force = weight of displaced fluid Pressure at depth: P = ρgh

16. Credits Fluid graphic www.physics- net.com/force/sf000.htm www.physics- net.com/force/sf000.htm Pressure cartoon www.physics.utah.edu/~mohit/Physi cs_Cartoons.html www.physics.utah.edu/~mohit/Physi cs_Cartoons.html

17. More Credits Pressure at depth, Pascal’s vases http:/titan.bloomfield.edu/facstaff/dnicolai/ Physics/Physica105/Phy105- lessons/lesson7-105.htm Hydraulic Press picture hyperphysics.phy- astr.gsu.edu/.../hpress.gif