1. Gravity, Friction, and Pressure
CHAPTER
NEW CHAPTER
Gravity, Friction, and Pressure
the BIG idea
Newton's laws apply to all forces.
Gravity, Friction, and Pressure
3.1
Gravity is a force exerted by masses.
3.2
Friction is a force that opposes motion.
3.3
Pressure depends on force and area.
3.4
Fluids can exert a force on objects.
CHAPTER OUTLINE

2. 3.1 Gravity is a force exerted by masses.
weight
Greater mass results in greater force.
orbit
Greater distance results in smaller force.
SECTION
OUTLINE

3. 3.1 gravity Gravity is a force exerted by masses.
weight
The force that objects exert on each other because of their mass.
orbit
KEY CONCEPT
SUMMARY

4. 3.1 weight Gravity is a force exerted by masses.
The force of gravity on an object.
orbit
KEY CONCEPT
SUMMARY

5. 3.1 orbit Gravity is a force exerted by masses.
weight
The elliptical path one celestial body follows around another celestial body; an object in orbit has a centripetal force acting on it that keeps the object moving in a circle or other ellipse.
orbit
KEY CONCEPT
SUMMARY

6. Friction is a force that opposes motion.
3.2
Friction is a force that opposes motion.
Frictional force depends on–
friction
• types of surfaces
fluid
• motion of surfaces
air resistance
• force pressing surfaces together
friction
SECTION
OUTLINE

7. Friction is a force that opposes motion.
3.2
Friction is a force that opposes motion.
Air resistance is a type of friction.
friction
air resistance
gravity
fluid
air resistance
SECTION
OUTLINE

8. 3.2 friction Friction is a force that opposes motion.
fluid
A force that resists the motion between two surfaces in contact.
air resistance
KEY CONCEPT
SUMMARY

9. 3.2 fluid Friction is a force that opposes motion.
A substance that can flow easily, such as a gas or a liquid.
air resistance
KEY CONCEPT
SUMMARY

10. 3.2 air resistance Friction is a force that opposes motion.
fluid
The fluid friction due to air.
air resistance
KEY CONCEPT
SUMMARY

11. Pressure depends on force and area.
3.3
Pressure depends on force and area.
Pressure =
Force
Area
pressure
Pressure in a fluid acts in all directions.
pascal
SECTION
OUTLINE

12. 3.3 pressure Pressure depends on force and area.
pascal
A measure of how much force is acting on a certain area; how concentrated a force is.
KEY CONCEPT
SUMMARY

13. 3.3 pascal Pressure depends on force and area.
The unit used to measure pressure; one pascal is the pressure exerted by one newton of force on an area of one square meter, or one N/m2.
KEY CONCEPT
SUMMARY

14. Fluids can exert a force on objects.
3.4
Fluids can exert a force on objects.
• Buoyant force is equal to the weight of the displaced fluid.
buoyant force
Bernoulli's principle
Pascal’s principle
• A faster-moving fluid produces less pressure than a slower-moving one.
SECTION
OUTLINE
• Pressure is transmitted through fluids.

15. 3.4 buoyant force Fluids can exert a force on objects.
Bernoulli's principle
The upward force on objects in a fluid; often called buoyancy.
Pascal’s principle
KEY CONCEPT
SUMMARY

16. 3.4 Bernoulli's principle Fluids can exert a force on objects.
buoyant force
Bernoulli's principle
Bernoulli's principle
A statement that describes the effects of movement on fluid pressure; according to this principle, an increase in the speed of the motion of a fluid decreases the pressure within the fluid.
Pascal’s principle
KEY CONCEPT
SUMMARY

17. 3.4 Pascal’s principle Fluids can exert a force on objects.
buoyant force
Pascal’s principle
Bernoulli's principle
A statement that says when an outside pressure is applied at any point to a fluid in a container, that pressure is transmitted throughout the fluid with equal strength.
Pascal’s principle
KEY CONCEPT
SUMMARY

18. 3.1 Gravity is a force exerted by masses.
I. Gravity is a force exerted by masses.
gravity
A. Masses attract each other.
weight
1. The Force of Gravity
orbit
2. Gravity on Earth
3. Weight and Mass
B. Gravity keeps objects in orbit.
1. Spacecraft in Orbit
2. People in Orbit
KEY CONCEPT
SUMMARY

19. Friction is a force that opposes motion.
3.2
Friction is a force that opposes motion.
II. Friction is a force that opposes motion.
friction
A. Friction occurs when surfaces slide against
each other.
fluid
air resistance
1. Forces and Surfaces
2. Friction and Heat
B. Motion through fluids produces friction.
KEY CONCEPT
SUMMARY

20. Pressure depends on force and area.
3.3
Pressure depends on force and area.
III. Pressure depends on force and area.
pressure
A. Pressure describes how a force is spread over an area.
pascal
B. Pressure acts in all directions in fluids.
C. Pressure in fluids depends on depth.
1. Pressure in Air
2. Pressure in Water
KEY CONCEPT
SUMMARY

21. Fluids can exert a force on objects.
3.4
Fluids can exert a force on objects.
IV. Fluids can exert a force on objects.
buoyant force
A. Fluids can exert an upward force on objects.
Bernoulli's principle
1. Buoyancy
Pascal’s principle
2. Density and Buoyancy
B. The motion of a fluid affects its pressure.
1. Bernoulli’s Principle
2. Applying Bernoulli’s Principle
C. Forces can be transmitted through fluids.
1. Pascal’s Principle
2. Hydraulics
KEY CONCEPT
SUMMARY