1. Motion
How fast is
fast?

2.  Frame of reference – a system used
Motion
 Motion – change in position relative
to a reference point.
 Frame of reference – a system used
to identify the precise location of an
object

3. Distance Vs. Displacement
 Distance: How far an
object has moved.
 SI unit = meter
 “Total steps taken”
 Total Displacement:
The distance and direction
of an object’s change in position
from the starting point
 Displacement includes direction
 “How far are we from where we started?”

4. Distance Vs. Displacement

5. SIDENOTE: Direction?!?!? by both magnitude AND direction
 Vector – quantity that is described
by both magnitude AND direction
 Ex: 10m/s south, 8m upward, 9.8m/s2 to
the ground

6. SIDENOTE:
Vector
 Distance is a Scalar (Just a number)
 Displacement is a Vector (A Number
and A
Direction)
 The image to the right shows
vector addition (multiple vectors). We will deal with this in a bit.
 The arrow length indicates
the magnitude of velocity
 Vector Video!!!

7. Speed and Velocity is moving changes it’s position
 Speed – how fast an object
moving
 Does NOT include a direction is
 Velocity – rate at which an object
changes it’s position
 Basically, it is how long it takes an object to get
from point A to point B
 Includes both magnitude AND direction

8. Speed vs. Velocity Units for:  Speed – distance / time
 Simply the magnitude of Velocity
 S = d/t
 Velocity – displacement / time
Speed WITH a direction
 V = d/t 
 SI 
Units for:
Distance+Displacement
Time = seconds (s)
= meters (m)
Speed+Velocity = meters/second (m/s)

9. Scalar vs Vector  Scalar (Just a number)
 Distance
 Speed
 Vector (A Number and A Direction)
 Displacement
 Velocity

10. Two Kinds of Speed We will almost ALWAYS calculate average speed total
divided
distance traveled
by the total time
 Ex: speed on trip to Orlando
from Chas
 Instantaneous Speed:
speed at a specific instant
 Ex: speedometer

11. Practice which travels from New York City hours? to Los Angeles (4800
 What is the speed of a commercial jet
which travels from New
York City
hours? to
Los
Angeles
(4800
km) in 6
 What would the velocity be?
 800 km/hr WEST

12. More Practice travels 355 seconds? speed meters of a bike that in
 What is the
travels 355 seconds?
speed
meters
of a bike
that in
103.7
 What would
the velocity be?
 3.42 m/s DOWNHILL

13. train travels 100 km/hr for 2 hours. What distance has it traveled? S
And Even
More Practice! A
train
travels
100
km/hr
for 2
hours.
What distance
has it
traveled? S =
d/t
= d /
100km/hr
2hrs
200km = d

14. SIDENOTE: Velocity  A vector is a quantity with a direction
 Notice speed has no + or –
 Velocity however, can be + or – magnitudes. That indicates a direction n
 A vector is a quantity with a
direction
 Positive velocity is right and up
 Negative velocity is left and dow

15. Unit 6.1: Motion
Assessment 1 will cover information from slides 1- 15

16. Position vs
Time
Graphs
Pictures say
1000
words…

17. Position vs Time Graphs graph.
 Motion can be studied using a position vs. time
graph.
 POSITION (or DISPLACEMENT) on the vertical axis
 TIME on the horizontal axis.
 The SLOPE of the line indicates the VELOCITY

18. Calculating Slope finding the change in position (y2 – y1) over the
 Slope (which is the velocity), can be calculated by
finding the change in position
(y2 – y1)
over the
change in time
(x2 – x1)
RUN OR
RISE
over

19. Calculating
Slope
 So let’s try it:

20. Calculating Slope 1) Choose 2 points to start y2 = x2 = and end at.2)
Calculate the change between the
Difference in Position (y) =
Difference in Time (x) =
Calculate
Slope = Position / Time
(y2 – y1) / (x2 – x1)
points. 3)
AND REMEMBER, SLOPE = VELOCITY

21. Different Slopes mean… a POSITIVE velocity greater the velocity the
 POSITIVE slope indicates
 Positive velocity means it is
a POSITIVE velocity
moving forward
greater the velocity
 The greater the slope,
the
 The less the slope,
the
smaller
the
velocity
Which has a greater
velocity?
A – It has a greater
slope and is steeper.

22. Different Slopes mean… a ZERO velocity Which has a greater velocity?
 ZERO slope indicates
a ZERO
velocity
horizontal
 Zero slope means
that
the
line is
Which has a greater
velocity?
They are both
the same. Neither is moving.

23. Different Slopes mean… Which has a greater negative velocity?
 NEGATIVE slope indicates a NEGATIVE velocity
 Negative velocity means
negative direction.
that
the
object is
traveling in
the
Which has a greater
negative velocity?
B – It has a greater slope, therefore a greater neg velocity

24. Put it all together… So what is happening at each of these positions?
B) C) D)
Moving forward
Stopped
Moving in negative
direction
Could you calculate
the velocity for each
portion?
YES!
Rise over Run

25. Unit 6.2: Position v. Time Graphs
Assessment 2 will cover information from slides

27. MOMENTUM  Momentum – the motion of mass
 If an object is moving, it has momentum
▪ An object with lots of momentum will be hard to stop.
▪ An object with little momentum will be easier to stop.

28. MOMENTUM  Law of Conservation of Momentum  Examples:
 Momentum is never created or destroyed, it can only be transferred
from one object to the next.
 The total amount of momentum in a system will be conserved.
▪ The TOTAL MOMENTUM in a system cannot increase or decrease.
 This applies any time 2 (or more) objects collide.
 Examples:
 When a pool ball is hit into a stationary pool ball, causing that
to move with the same momentum
2nd
ball
 When a golf club hits a golf ball off of a tee, the momentum of the
golf club will be transferred to the ball.
 Two football players hitting each other on a football field.

29. MOMENTUM Momentum of Object1 P1 M1 * V1 = Momentum P2 M2 * V2
 Momentum is CONSERVED.
Never created or
destroyed. So in our simple examples…
 The equation:
Momentum of Object1 P1
M1 * V1 =
Momentum P2
M2 * V2
of Object2 M1 V1 =
mass of
1st
object
M2 = mass of
2nd
object
velocity of
1st
object
V2 = velocity of
2nd

30. MOMENTUM with a mass of 12kg, what will be the velocity that the
 A 3kg ball is traveling at 8m/s. If it hits an empty bottle,
with a mass of 12kg, what will be the velocity that the
bottle travels assuming the ball stops
momentum is transferred? on
impact
and
all
M1 * V1 =
M2 * V2
So if we knew that…
3kg * 8m/s
24kg*m/s =
12kg * V2 =
V2 = 2m/s

31. ACCELERATION

32. Review that: measure of distance over time direction  Remember
 Speed is a
measure of
distance over time
 How long it takes you to get from one place to another
 Velocity was speed in a
direction

33. Scalar vs Vector  Vector (A Number and A Direction)
 Scalar (Just a number)
 Distance
 Speed
 Magnitude of Acceleration
 Vector (A Number and A Direction)
 Displacement
 Velocity
 Acceleration

34. What is acceleration?  Change  Change in velocity can be caused by:
 Acceleration is the rate of change of velocity.
 A change
in velocity can be
caused
by:
 Change
 Speed
in speed
up or slow down
 Change
in direction

35. 3 ways to cause acceleration Direction at green light
 Increasing speed
 Example: Car speeds up
at green light
 Decreasing speed
screeeeech
 Example:
Car slows down at stop light
 Changing
 Example:
Direction
Car takes turn (can be at constant
speed)

36. Zero Acceleration be changing to be zero, the velocity cannot
 For acceleration
be changing
to be zero,
the velocity cannot
 ONLY when you
in one direction
are traveling at a constant speed
 So, would it still be zero if you were traveling at a constant speed in a circle?

37. The Math a = change in velocity change in time acceleration Vf –Vi
divided by the
a = change in
velocity
change in
time
 A =
Vf –Vi t
 Units
= m/s2
 m/s2 ALWAYS means
acceleration

38. FORMULAS:
 A = Vf – Vi t
 T = Vf – Vi A
 Vf = (A x t) + Vi

39. The numbers never lie… means velocity is increasing gradually rapidly
 A SMALL acceleration
means
velocity is
increasing
gradually
 A LARGE acceleration
rapidly
means
velocity is
increasing
 A POSITIVE acceleration means an object is
speading up
 A NEGATIVE acceleration means an object is
slowing down
 This is called deceleration

40. Example your velocity goes from 10 m/s to 40 m/s in 5 secs.
 You are driving from school home and
your velocity goes from 10
m/s in 5 secs.
m/s to 40
 What is your acceleration?

41. Example a football is thrown from rest with an acceleration of
 If
a football
is thrown from rest with an
acceleration of
8.5 m/s2, and had an
25m/s, how long was
final velocity of
the football accelerating?

42.  In a vacuum, things fall towards
Gravity and
Acceleration
 Gravity is the force that pulls
everything toward the center
of the Earth
 Acceleration due to Gravity = 9.8m/s2
 In a vacuum, things fall towards
9.8m/s2 every second
 A vacuum is a space entirely void of matter
the
earth at
 When not in a vacuum, air resistance will slow down a falling object.
Hammer vs Feather on the Moon (1 min)

43. Gravity
and Slinky!
 Just cuz it looks cool …

44. Falling From Space over 24 MILES up exactly 1
 In a vacuum, things fall towards the
9.8 m/s2 every second
earth at
 Jumps from
over 24 MILES up
 At
exactly
exactly exactly 1 2 5
second, traveling at 9.8m/s
seconds, traveling at 19.6m/s seconds, traveling at 49m/s

45. Gravity and Acceleration objects to stop accelerating and reach a
 In real life, sometimes wind resistance causes
objects to stop accelerating
and
reach a
maximum
velocity
 This is what causes
“Terminal Velocity”
 Terminal Velocity for a falling
Human is ~56 m/s (~120mi/hr)

46. Law of Universal Gravitation object. But the pulls aren’t all equal.
 Technically, gravity pulls everything towards
everything else
 Every object exerts a gravitational pull on every other
object.
But the pulls aren’t all equal.
They depend on a
few things
 The gravitational force between
depends on 2 things:
 The MASS of the both objects
two objects
 As the masses increase, the gravitational force INCREASES
 The DISTANCE between the two objects
 As the distance increases, the gravitational force DECREASES.

47. Universal Gravitation: Math  r = distance between 2 objects
 M1 = mass
 M2 = mass
of object 1
of object 2
 r = distance between 2 objects
 G = universal gravitational constant
= x10-11 N-m2/kg2
While standing on the Earth’s surface, you are m from the center. What is the gravitational force between earth (m= x1024 kg) and you (m=75kg)?

48. Universal Gravitation: Math
Compare that to 2 students that each have a
mass of
75kg
and are only 1m apart.
G = universal gravitational constant
= x10-11 N-m2/kg2
 F =
G (M1 * M2) r2
Compare that to gravitational force between
and the earth?
F = N
you (at
150lbs)

49. Unit 6.3: Momentum, Acceleration and Gravity
Assessment 3 will cover information from slides

50. ACCELERATION
GRAPHS
Pictures are worth even MORE than words now!

51. Knowing this, what do you think
RECALL…
Motion can be graphed
Acceleration is merely a
speed over time
change in
Knowing this, what do you think
the two axis of our acceleration
graphs are going to be?

52. ACCELERATION GRAPHS  SLOPE = Acceleration
 The vertical axis (y) will be velocity (m/s)
 The horizontal axis (x) will be time (s)
 SLOPE = Acceleration

53. GRAPHING  How can you tell? these is a velocity graph,
AND ACCELERATION
Which of
these is a velocity graph,
and which is an acceleration graph?
 How can you tell?

54. velocity changes over time
VS TIME
GRAPHS
Velocity v. Time graph shows
velocity changes over time
how
ANY slope
at all shows an
acceleration

55. POSITIVE acceleration
DIFFERENT SLOPES…
A POSITIVE slope means there is
POSITIVE acceleration
 Positive acceleration
means
speeding up
Which of these lines
has a greater acceleration?
B – It has a greater slope

56. acceleration of 0m/s2 DIFFERENT SLOPES…
A slope of ZERO shows an
acceleration of 0m/s2
 This just means there is a constant
speed
 Slope of zero = horizontal
line
Which of these lines
has a greater acceleration?
Neither – Both are zero
has a greater velocity?
A – It has velocity of 130m/s

57. NEGATIVE acceleration
DIFFERENT
SLOPES…
A NEGATIVE slope means there is
NEGATIVE acceleration
 Negative acceleration means slowing
down
 Slowing down =
DECELERATING
Which of these lines
has a greater deceleration?
A – It has a greater
slope

58. Positive acceleration
SLOPES:
RECAP
Line slopes up
Velocity is increasing
Positive acceleration
Line slopes down
Velocity is decreasing
Negative acceleration
Straight Horizontal
line
Constant velocity
No acceleration

59. CALCULATING ACCELERATION is the formula for acceleration?
 What is
the
formula for acceleration?
velocity at 1
velocity at 4
acceleration s?
between 1
and 4
seconds?
A = (Vf-Vi) t
= (2m/s – 8m/s)
3 s
- = - 6 m/s =
-2 m/s2 - 3s

60. PUTTING IT ALL TOGETHER Tell me what is happening for each line A A
– Decelerating B
– Constant velocity (0 m/s)
AND no acceleration. This
is STOPPED. C
– Acceleration D
– Constant velocity (15 m/s)
AND no acceleration.
is NOT STOPPED
This

61. Unit 6.4: Velocity v. Time Graphs
Assessment 4 will cover information from slides