Bernoullis Pascals Archimedes Principles of Lift Buoyancy and
Bernoulli’s, Pascal’s, & Archimedes’ Principles of Lift, Buoyancy, and Pressure
A. Bernoulli’s Principle ¡As the Velocity (speed) of a fluid increases, the Pressure exerted by the fluid decreases ¡Why?
A. Bernoulli’s Principle Airplane lift View airplane wings explanation. Curve Ball
B. Archimedes’ Principle ¡The buoyant force on an object in a fluid is equal to the weight of the fluid displaced by the object
B. Archimedes’ Principle ¡The upward force of a Fluid exerted on an object. ¡What is the downward Force exerted on an object? Gravity
B. Archimedes’ Principle From Archimedes’s Principle : Buoyant Force = Weight of fluid displaced = mg (note : F = ma) = Vg (note : = m ) V Thus FB = Vg FB = Buoyant Force or Upward thrust = Density of fluid V = Volume of fluid displaced or the volume of the object that
B. Archimedes’ Principle Mass = 20 g Volume = 20 ml Mass of Fluid= 20 g
B. Archimedes’ Principle Gravity = 20 Object is in Liquid Buoyant Force = 20
B. Archimedes’ Principle Mass = 50 g Volume = 20 ml Mass of Fluid= 20 g
B. Archimedes’ Principle Gravity = 50 Object SINKS Buoyant Force = 20
B. Archimedes’ Principle Mass = 30 g Volume = 60 ml Mass of Fluid= 60 g
B. Archimedes’ Principle Gravity = 30 Object Floats Buoyant Force = 60
B. Archimedes’ Principle ¡ 1. 2. 3. Recall Fg= mg and Fb= V g If the buoyant force is less than the force of gravity (Fb<Fg) the object will sink If the buoyant force is greater than the force of gravity (Fb>Fg) the object will float If the buoyant force is equal to the force of gravity (Fb=Fg) the object will maintain the same depth
B. Pascal’s Principle ¡ pressure applied to a fluid is transmitted unchanged throughout the fluid View hydraulics explanation.
B. Pascal’s Principle ¡ A car weighing 1000 N sits on a 250 m 2 platform. What force is needed on the 10 m 2 plunger to keep the car from sinking? GIVEN: WORK: Platform: F = 1000 N A = 250 m 2 Plunger: F=? A = 10 m 2 1000 N = 250 m 2 F 2 10 m 2 (1000 N)(10 m 2)=(250 m 2)F 2 = 40 N
B. Pascal’s Principle Force ? Force = 15, 000 N Area of A = 8 cm 2 A B Area of B = 50 cm 2 How much force must you apply on A to lift the object on B?
B. Pascal’s Principle FA = 15, 000 N 8 cm 2 50 cm 2 A B FA =(8 cm 2)(15, 000 N) 50 cm 2 FA = 2, 400 N
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