PHYS 2101 Lecture : Lecture 27
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There"s a hw on gravitation and fluids due on monday (tues?) Chapter 15: fluids liquid or gas (incompressible vs compressible) no shearing stress --> it ows. 1) what is a uid : pressure p = Units pascal = pa = n/m2 = kg/(m s2) 1 atm = 1. 01 105 pa = 760 torr = 14. 7 lb/in2 (at ~ sea level) Note: density solid > liquid > gas pat h. Today, we"ll finish fluids and start oscillations . 15 (oscillations) and then do waves i: pascal"s principle. Buoyancy - lift a rock under water - its light. Take it above water - its heavy. Buoyant force is exerted upward by fluid. Consider a cube in a fluid with density and area a. (forget about the pressure on top of the fluid, i. e. atmospheric pressure: at top, fluid exerts a force on cube: Downward: at bottom, fluid exerts a force on cube: Upward: net force due to fluid is bouyant force:
