Presentation on theme: "Other Effects of Fluids (Pascal’s Principal and Bernoulli's Principal)"— Presentation transcript:
1 Other Effects of Fluids (Pascal’s Principal and Bernoulli's Principal) Chapter 4 Section 3Other Effects of Fluids(Pascal’s Principal and Bernoulli's Principal)
2 I. Pascal’s PrinciplePascal’s Principle- when pressure is applied to a fluid in a closed container, the pressure increases by the same amount everywhere in the containerObserved with hydraulics (machines operated by fluid)B. Hydraulic Device- consists of two pistons (moving plunger), one at each end of a U-shaped tube.
4 I. Pascal’s Principle1) System A – Full of fluid and press down on left piston. The increase in fluid pressure is transmitted to the right piston.a) Both pistons experience the same fluid pressureb) Because both pistons have the same surface area, they will experience the same force.
5 I. Pascal’s Principle2) System B– The right piston has a greater surface area than the left.a) Area of the small piston is 1 cm² and the area of the large piston is 9 cm².b) The right piston has an area 9 times greater than the left piston.c) Push on the left piston, pressure is transmitted equally to the right.d) Because area of right piston is 9 times greater, force on the left is multiplied by 9
6 II. Hydraulic Systems Use Pascal’s Principle A. Changing piston area results in changed forceHydraulic system- liquids transmit pressure in a confined fluid.a) When force is applied to a small piston (small area) it is multiplied when acting on a larger piston (large area) at the other endb) increased pressure is transmitted through fluid, which pushes on a larger piston surface area same pressure over larger area results in more force.
7 II. Hydraulic Systems 2) Common hydraulic systems Hydraulic liftshydraulic brakes3) Hydraulics are Long Lasting- since they use fluids to transmit pressure, hydraulic systems have few moving parts that can jam, break, or wear down.
8 II. Hydraulic Lifts 4) Hydraulic lift Uses a) Mechanics raise cars b) Lift ladders on fire trucksc) Dump trucksd) Cranes
9 II. Hydraulic Brakes 5) Hydraulic Brakes a) Driver pushes on the pedal, which pushes on small pistonb) The piston exerts pressure on the brake fluidc) Pressure is transmitted through fluid to larger pistons within the wheelsd) Each these piston pushes on a brake pade) System multiplies force with only a slight push allowing you to stop a large car
11 III. Bernoulli’s Principle Fluid Motion- fluids naturally flows from an area of high pressure to an area of low pressure.Ex: Drinking from strawAir removed from straw, creating an area of low pressureOutside high pressure pushes down on the surface forcing the drink upB. Bernoulli’s Principle- pressure of a fluid decreases when the speed of that fluid increases.
12 III. Bernoulli’s Principle 1) Demonstration:a) Fill the bagb) Raise the paperc) Make the ping-pong ball floatExplain how these demonstrations work2) Bernoulli’s Principle- helps explain how planes fly, why smoke rises up a chimney, how roof can fly off in high winds, and how soccer ball curves.
13 III. Bernoulli’s Principle Objects Shape- Design can cause air to move at different speeds above and below objectIf air above object is faster this results in fluid pressure pushing object upwardIf the air moves faster below the object, fluid pressure pushes it downward.
14 III. Bernoulli’s Principle Airplane Flight- The wing of an airplane is designed to produce lift (an upward force).Because the wing is slanted, the air that hits it is forced downward as the plane moves.Air exerts an equal but opposite force on the wing and pushes it upward (Newton’s 3rd Law)This helps the plane take off
15 III. Bernoulli’s Principle Faster-moving air following the disk’scurved upper surface exerts less pressure thanthe slower-moving air beneath itAir flows over top and bottom in same amount of time, however the top has more distance for air to flow across, the air is actually moving fasterAvg. Speed = Total Distance/Time
17 III. Bernoulli’s Principle Chimneys- smoke rises partly because hot air rises, and partly because it is pushed.1) Wind blowing across the top of a chimney lowers the pressure.2) Higher pressure at the bottom pushes air and smoke up the chimney.