1. WHAT IS A FORCE?
A force is a push or a pull, and one body exerts a force on another
SI units are Newton (N), 1N=1kg x m/s2

2. Effects of forces on objects
Balanced forces – forces are equal in size & opposite in direction
Net force – force that changes the velocity of the object
Object accelerates in the direction of the greater force

3. Friction
A force that opposes motion between two surfaces that are touching each other
Amount of friction depends on 2 factors
the kinds of surfaces
the force pressing the surfaces together

4. Four types of Friction
Static friction: force that acts on objects that are NOT moving, acts in direction OPPOSITE to that of the applied force
Sliding friction: force that opposes the direction of motion of an object as it slides over a surface (less than static)

5. Four types of Friction
Rolling friction: force that acts on rolling objects (less than static or sliding)
Fluid friction: opposes motion of
an object through
a liquid or gas

6. Gravitational Force
Gravity – the attracting force exerted by every object on every other object
Amount of gravitational force between objects depends on 2 things…

7. Gravitational Force 1)-mass 2)-distance
a) more mass=more g force
b) less mass=less g force
2)-distance
a) greater distance=less g force
b) lesser distance=more g force

8. ACCELERATION DUE TO GRAVITY
Falling objects accelerate at 9.8 m/s2 *same for ALL objects (in a vacuum with no air resistance)
This means that for each second the body is falling, its velocity increases by 9.8 m per s 

9. Air Resistance The force that air exerts on a moving object
Amount of air resistance depends on:
Speed 2. Size
3. Shape 4. Density

10. Terminal Velocity
The highest velocity that will be reached by a falling object
Downward force of gravity equals the upward force of air resistance

11. Projectiles Anything shot/thrown through the air
A thrown ball has constant horizontal velocity
Gravity pulls the ball downward
Vertical acceleration increases, changing the direction of the projectile to forward and downward

12. Constant horizontal velocity

13. Circles
Centripetal Acceleration: towards the center of a curved or circular path

14. Circles
Centripetal Force exerted toward the center of a curved path; without this force object will shoot off in a straight line in the direction it was traveling

15. Newton’s 1st Law “If I push it, it goes”
States that an object moving at a constant velocity keeps moving at that velocity unless a net force acts on it. If an object is at rest, it stays in rest unless a net force acts on it.
“If I push it, it goes”
Also called the law of inertia

16. Inertia Tendency of an object to resist any change in its motion
If an object is moving, it keeps moving at that speed and direction unless a force acts on it.
If an object is at rest, it stays at rest unless a force acts on it (velocity at rest = 0m/s)

17. Inertia The more mass an object has, the greater its inertia
More force would be needed to change the velocity of the object w/ greater inertia (which also means greater mass)

18. Newton’s 2nd Law
The acceleration of an object is equal to the net force acting on it divided by the object’s mass, a=F/m or simply F=ma
The amount of acceleration is affected by
size of the force
mass of the object

19. Weight or Force due to gravity
The measure of the force of gravity on an object Fg=W=mg
measured in Newtons (N)
2. 1kg=9.8N
(1N=0.22 pounds)
2.156lb = 1.0 kg
Weight or Force due to gravity
Acceln due to gravity
mass

20. Mass The amount of matter in an object
constant independent of location
measured in grams (g) and kilograms (kg)
**Find your mass in kg then your weight in Newtons.

22. Momentum More mass = More momentum More velocity = More momentum
Momentum is transferred

23. Law of conservation of Momentum
In a closed system, the loss of momentum of one objects equals the gain in momentum of another object – momentum is CONSERVED

24. Problem Review Activity
Each person will be assigned a color (yellow, orange, or red)
On notebook paper, you will solve the problems only for the color you are assigned
To receive full credit, you must…
1. Write down your “givens” (v = 3m/s, etc.)
2. Show your work to solve the problem
3. Put a box around your answer
4. Write all units!

25. Please add the following questions to the end of your test…
31. Calculate the acceleration of a car that accelerated from 5 m/s to 10 m/s in 2 s.
32. Calculate the acceleration of a car that slowed down from 10 m/s to 5 m/s in 2 s.
33. Calculate the momentum of a 12 kg object traveling at a velocity of 6 m/s.
34. Name one thing you have enjoyed about physical science so far.
35. Name one activity you wish we did more of in physical science.

26. PhysiFacts /30
13. What is the velocity of a car that covered 20km in 2 hours?
14. What is the acceleration of an object that accelerated from 5m/s to 10m/s in 2 seconds?
15. How much force needs to be applied to an 5km object to accelerate it at a rate of 2m/s2?
16. Calculate the momentum of a 3kg object moving at a rate of 3m/s.

27. Force and Motion Review
To review before test corrections…
Each table will be assigned a topic
Using the chalk markers, you will create a review “poster” on the surface of your tables
You will have 15 minutes to design before groups will rotate around the room to see each “poster”
Test corrections will follow this activity

28. Review Topic Assignments
Group 1: Newton’s Laws
Group 2: Velocity and Acceleration
Group 3: Momentum and Force equations
Group 4: Vocabulary Review
Group 5: Distance – Time Graphs and Speed – Time Graphs

29. Group ____: Newton’s Laws
Write out each one of Newton’s three laws of motion
Draw a picture for each law
Define inertia
If something has more mass, does it have more inertia?

30. Group ____: Velocity &Acceleration
Define velocity
Write the equation & the circle for velocity
Define all units for velocity
Solve 3 practice problems and SHOW WORK!
Define acceleration
Write the equation for acceleration
Define all units
Solve 1 practice problem and SHOW WORK!

31. Group ____: Momentum & Force
Define force
Write the equation and the circle for force
Define all units for the force equation
Solve three practice problems and SHOW WORK!
Define momentum
Write the equation and the circle for momentum

32. Group ____: Vocabulary Review Include the following terms and choose 5 to draw a picture for
Terminal velocity
Velocity
Acceleration
Momentum
Force
Friction
Net force
Balanced force
Static Friction
Fluid Friction
Sliding Friction
Rolling Friction

33. Group _____: The Graphs
Distance-Time Graph
Draw an example and label the x-axis and y-axis
What does the slope tell you?
What does a horizontal slope tell you?
Speed-Time Graph

34. PhysiFacts /18
1. A car increases it’s velocity from 0 m/s to 14 m/s in 2 seconds. Solve for acceleration.
2. How long will your trip take (in hours) if you travel 350 km at an average speed of 80 km/hr?
3. A racing car’s velocity is increased from 44 m/s to 66m/s in 11 seconds. Solve for acceleration.

35. Chapter 11 Assessment – p. 350-351
Will count as a quiz grade!
1-10 – just write the letter answer
Draw the concept map and fill it in

36. IAN pg. 29: Types of Friction
Define FRICTION
List the two factors that determine the amount of friction
Draw a box with four sections for each of the four types of friction: static, sliding, rolling, fluid
Define and draw a picture for each type of friction

37. Agenda: 4/19
Place cell phone in a pouch – you do not need a calculator today!
Be in your seat and ready to start when the bell rings!
Today’s Order of Operations:
PhysiFacts
Motion Video
Defining Motion IAN page 30
Vocab Review Game
End of the grading period is April 24!
IAN pages due FRIDAY APRIL 27!

38. PhysiFacts 5.2 4/19 4. Name the four types of friction.
5. A push or pull that one body exerts on another =
6. Newton’s First Law:
7. Newton’s Second Law:
8. Newton’s Third Law:

39. Agenda: 4/23
Place cell phone in a pouch – you DO NOT need a calculator today!
Sit in groups of FOUR and get out your notes!
Be in your seat and ready to start when the bell rings!
Today’s Order of Operations:
PhysiFacts
IAN page 31: Newton’s Laws of Motion
Ping Pong Soccer Lab
TIME FOR MAKE UP WORK!
Reminders: end of grading period is TOMORROW!

40. PhysiFacts /23
9. The amount of gravitational force depends on… (2 things)
10. Forces equal in size and opposite in direction =
11. SI unit for force =
12. The highest velocity that will be reached by a falling object

41. IAN page 31: Newton’s Laws of Motion
Newton’s First Law
What does the law state?
What is another name for this law?
Define inertia.
Newton’s Second Law
What is the equation associated with this law?
Newton’s Third Law
What does this law state?
DRAW AN ILLUSTRATION FOR EACH LAW!

42. Today’s Order of Operations:
Agenda: 4/24
Keep cell phone today!
Turn in any labs from yesterday!
Be in your seat and ready to start when the bell rings!
Today’s Order of Operations:
Paper Airplane Lab
Time for make up work including Ch. 12 guided outline!
Reminders: end of the grading period is TODAY!, Forces and Motion Test on FRIDAY! IAN pages due FRIDAY!

43. Problem Review Activity
Each person will be assigned a color (yellow, orange, or red)
On notebook paper, you will solve the problems only for the color you are assigned
To receive full credit, you must…
1. Write down your assigned color at the top of your paper
2. Write down your “givens” (v = 3m/s, etc.)
3. Show your work to solve the problem
4. Put a box around your answer
5. Write all units!

44. Force, Mass and Acceleration IAN page 32
Draw the circle AND write the equation for Newton’s second law
Define the variables and the units for each part of the equation
Solve the practice problems

45. IAN page 33: Momentum Define momentum
Draw the circle AND write the equation for momentum
Define variables and units for each part of the equation
Solve the three practice problems