1. Bernoulli’s, Pascal’s, & Archimedes’ Principles
Principles of Lift, Buoyancy, and Pressure

2. A. Bernoulli’s Principle
As the Velocity (speed) of a fluid increases, the Pressure exerted by the fluid decreases
Why?

3. A. Bernoulli’s Principle
Airplane lift
Curve Ball
View airplane wings explanation.

4. B. Archimedes’ Principle
The buoyant force on an object in a fluid is equal to the weight of the fluid displaced by the object

5. B. Archimedes’ Principle
The upward force of a Fluid exerted on an object.
What is the downward Force exerted on an object?
Gravity

6. B. Archimedes’ Principle
From Archimedes’s Principle :
Buoyant Force = Weight of fluid displaced
= mg (note : F = ma)
= Vg (note :  = m ) V
Thus FB =  V g
FB = Buoyant Force or Upward thrust
 = Density of fluid
V = Volume of fluid displaced or
the volume of the object that immersed in the fluid.
g = force of gravity

7. B. Archimedes’ Principle
Mass = 20g
Volume = 20ml
Mass of Fluid= 20g

8. B. Archimedes’ Principle
Gravity = 20
Buoyant Force = 20
Object is in Liquid

9. B. Archimedes’ Principle
Mass = 50g
Volume = 20ml
Mass of Fluid= 20g

10. B. Archimedes’ Principle
Gravity = 50
Buoyant Force = 20
Object
SINKS

11. B. Archimedes’ Principle
Mass = 30g
Volume = 60ml
Mass of Fluid= 60g

12. B. Archimedes’ Principle
Gravity = 30
Buoyant Force = 60
Object
Floats

13. B. Archimedes’ Principle
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

15. View hydraulics explanation.
B. Pascal’s Principle
pressure applied to a fluid is transmitted unchanged throughout the fluid
View hydraulics explanation.

16. B. Pascal’s Principle Platform: 1000 N = F2 F = 1000 N 250 m2 10 m2
A car weighing 1000 N sits on a 250 m2 platform. What force is needed on the 10 m2 plunger to keep the car from sinking?
GIVEN:
Platform:
F = 1000 N
A = 250 m2
Plunger:
F = ?
A = 10 m2
WORK:
1000 N = F2
250 m m2
(1000 N)(10 m2)=(250 m2)F2
F2 = 40 N

17. B. Pascal’s Principle A B Force ? Force = 15,000 N Area of A = 8 cm2
Area of B = 50 cm2
How much force must you apply on A to lift the object on B?

18. B. Pascal’s Principle A B FA = 15,000N 8 cm2 50cm2
FA =(8 cm2)(15,000 N)
50cm2
FA = 2,400 N