1. Unit 2: Matter Chapter 3: States of Matter Section 3: Fluids

2. Bell Ringer Check your file!!
Have you turned in your Science in the News assignment??
Test on Chapter 3 WEDNESDAY
Unit 2 Test FRIDAY
Get out your notes and get ready

3. Pressure
Pressure – the amount of force exerted per unit area of a surface
Fluids exert pressure evenly in all directions
P=force/area
Measured in pascals (Pa)

4. Buoyant force
Buoyant force – the upward force that keeps an object immersed in or floating on a fluid
Results from pressure increasing with depth
Object continues to sink until the forces pushing it up and greater than those pulling it down

5. Buoyant Force
Archimedes Principle – the buoyant force on an object in a fluid is an upward force equal to the weight of the fluid that the object displaces
if the weight of the water displaced is equal to the buoyant force, the object will float
Sink or float also based on density

9. Pascal’s Principle
Pascal’s Principle – a change in pressure at any point in an enclosed fluid will be transmitted equally to all parts of the fluid
P1 = P2
F1/A1 = F2/A2.

10. Pascal’s Principle
A hydraulic lift uses Pascal’s principle to lift a 19,000 N car. If the area of the small piston (A1) equals 10.5 cm2 and the area of the large piston (A2) equals 400 cm2, what force needs to be exerted on the small piston to lift the car?
1. List the given and unknown values.
Given: F2 = 19,000 N A1 = 10.5 cm2
A2 = 400 cm2
Unknown: F1

11. F1 = 500 N

12. Fluids in Motion
Fluids move faster through small areas than through larger areas, if the overall flow rate remains constant
Viscosity – the resistance of a gas or liquid to flow
Honey is more viscous than water
Fluid pressure decreases as speed increases

13. EXIT SLIP
What is buoyant force?