1. MOTION
Anatasari Surya, S.Pd
Junior High School State 1 Metro1

2. To understand the concept of
movement, work, force, and
energy in our daily life
Standard Competence
2

3. To analyze experimental data
of uniform straight motion
and uniformly accelerated
straight motion, and its
application in everyday life
Basic Competence
3

4. • To find the characteristics of Uniform Linear Motion
• To define acceleration as a speed changes per time
taken
• To find the distance based on time taken
Indicator
4

5. • Motion
• Virtual Motion
• Relative motion
• Point of reference
• Distance
• Displacement
• Speed
• Velocity
• Acceleration
• Deceleration
• Uniform motion
• Uniformly
acceleration motion
5
Science Words

6. Use the ground as reference!
What she is move?
Look at the picture!
6

7. What bird is move..?
Use the ground as reference
7

8. Mention the objects are move and motionless!!
Use the ground as reference
8

9. • Motion is a change of position with respect to a
point of reference.
• Point of reference is something that is considered
fixed and used as a comparison.
• Motion very dependent on point of reference
– Satu titik acuan melihat suatu gerak sangat lambat
– Titik acuan lain melihatnya sangat cepat
– Sedangkan titik acuan yang lain lagi melihatnya diam
Conclude:
9

10. .....
• Motion dependent on point of reference is
relative motion
• Virtual motion is looks like motion but actually
it is not motion, example:
– Sun rises in the east and sets in the west
– When you are inside a moving bus and look
towards the window you will see trees moving
away from you.
10

11. Distance = 200 m
Displacement = 200 m to rigth
200 m
What is difference
between distance and
displacement?

12. 0 1 2 3 4 5 6 7 8 9
A C
B
2 134
Distance = 13 m
Displacement = 5 m to rigth
m
What is difference
between distance and
displacement?

13. conclude
• Distance is length of all lines passed through
by an object
scalar quantity -> have: magnitude and unit
• Diplacement is position change of an object
from the initial point
Vector quantity ->
have: magnitude, unit,
and direction

14. Distance = 35 m
Displacement = 15 m to left
What its distance?
What its displacement?
10 m
25 m
1.

15. What difference between
a distance and
a displacement ?
120 m
150 m
150 m
Distance =
Displacement =
A
B
C
270 m
90 m
Exercise!
2.

16. A
B
30 meters
30 meters
Romi run around from A to B.
Calculate the distance and
displacement!
Exercise
Distance = 60 m
Displacement = √1800 m
= 30 √2 m
3.

17. 4. Initial position of adi is 0 m from the
reference of point. He walking as far as 5 m
to right and then return to left as far as 9 m.
Calculate the distance and displacement!
-4 -3 -2 -1 0 1 2 3 4 5 m

18. Speed and Velocity

19. 0 4
Time (second)
the moving object is identified by its change of
position of a point of reference
If we want to know how far the position has
changed, we must know the concept about
velocity
Why the change of position of car is longer
than a bicycle?

20. Speed = the number of velocity.
(scalar quantity)
Speed = distance
time
Velocity = the change of position of each time.
(vector quantity)
Velocity = displacement
time

21. scalar quantity:
Speed = magnitude, and unit
vector quantity:
Velocity = magnitude, unit and direction
For example:
The speedometer of motorcycle shows 50 km/hour to west
• Speed = 50 km/hour
• Velocity = 50 km/hour to west

22. What difference between
a distance and
a displacement ?
200 m
250 m
150 m
Distance =
Displacement =
A B
C
450 m
150 m
Speed and Velocity
If Budi go to C from A in 5
seconds that :
Speed =
Velocity =
90 m/s
30 m/s

23. A
B C
D
E
500m
200 m
300 m
400 m
350 m

24. Exercise:
Yuni runs 120 m in 1 minute.
What is her running speed?
Known :
s = 120 m
t = 1 minute = 60 s
Question : V =….?
Answer :
V = s / t
= 120 / 60
= 2 m/s

25. • a friend told you that he could ride his bike at
a speed of 18 km/hour. To find out whether
you could ride faster, you needed 30 seconds
to go as far as 180 m. Who rade faster, your
or your friend?

26. Average speed
Average speed is the total traveled distance divided
by the total time needed to travel that distance
• Average speed = total distance
total time
v = s1 + s2 + s3 ……
t1 + t2 + t3 ….

27. Example
Budi rides a bicycle traveling 20 km in 20 minutes. And then
he travels 16 km in 10 minutes. Find the Budi’s average
speed! State your answer in meter/second.
s = 20 km + 16 km = 36 km = 36,000 meter
t = 20 minutes + 10 minutes = 30 minutes = 1800 seconds
v = s : t
= 36,000 m : 1800 s
= 20 m/s
7

28. v = s1 + s2 + s3
t1 + t2 + t3
= 5000 + 10000 + 10000
600 + 900 + 300
= 25000
1800
= 13.89 m/s b. 50 km/hour

29. Exercise :
1. The velocity of a car when it is moving are as follow:
 the first 10 minutes, the distance is 5 km.
 the second 15 minutes, the distance is 10 km
 the third 5 minutes, the distance is 10 km.
Calculate :
a. the average velocity
b. express the average velocity in km/hour.

30. 2. Sebuah bus melaju di jalan tol yang lurus.
Selama 30 menit pertama bus itu menempuh
jarak 45 km, 15 menit selanjutnya
menempuh jarak 15 km, dan 15 menit
selanjutnya menempuh jarak 20 km.
Calculate the average speed that bus!

31. LINEAR ACCELERATE MOTION
(LAM)
It is linear motion whose
velocity is changing/varying
regularly

32. ACCELERATION
• Symbol: a
• Formula:
acceleration = change of velocity
time taken
• SI Unit : m/sec2
• The same formula can also be applied for
deceleration, but the value of a is
negative

33. Acceleration
• Acceleration denotes the change of velocity
per unit of time. (Vector Quantity)
acceleration
decleration
• The formula :
a = vt – v0 or a = v/ttt – t0
With : a = acceleration (m/s2)
vt = The final velocity (m/s)
v0 = the initial velocity (m/s)
velocity acceleration velocity acceleration

34. Equation of Motion
• Mathematical relations relating motion variables are
called equation of motion
• For motion with constant acceleration, the variables are:
• Displacement : s
• Initial velocity : v0
• Final velocity : vt
• Constant acceleration : a
• Time taken : t

35. Examples
1. A car changed its speed from 36 km/hour to 72
km/hour in 10 seconds. Calculate the car’s
acceleration.
Known : vo = 36 km/hour = 10 m/s
vt = 72 km/hour = 20 m/s
t = 10 s
Question : a …?

36. Answer :
• a = vt – vo
•
• = 20 – 1010
= 1 m/s2
t

37. • A car changed its speed from 36 km/hour to
54 km/hour within 10 seconds. Calculate the
car acceleration!
• a truck move by velocity as 7 m/s in 1 second.
and then in 2 second the velocity becomes 9
m/s. Calculate the acceleration?

38. Linier Motion
• Linier motion is defined as a motion that has a
linier path.
• Linier motion with constant velocity is called a
regular linier motion.
• Linier motion with constant acceleration is
called a dynamic linier motion.

39. Displacement-time graph
• A displacement-time graph shows how the
displacement of an object changes with time.
• The gradient of a displacement-time graph
represents the velocity of the object.

40. Displacement (m)
Time (s)
Zero gradient – stationary object

41. Displacement (m)
Time (s)
Fixed gradient-uniform velocity

42. Displacement (m)
Time (s)
Increasing gradient – increasing velocity

43. Displacement (m)
Time (s)
Decreasing gradient – decreasing velocity

44. Graph of Linier Motion
• Graph distance on the y-
axis and time on the x-
axis
• The velocity is 2 m/s
●
Slope = rise = distance = speed
●
run time
N
o
Distance
(m)
Time
(s)
1 20 10
2 40 20
3 60 30
4 80 40
5 100 50
6 120 60

45. Distance - Time Graph
• If something is not
moving, a horizontal line is
drawn.
• If something starts out
slow and then speeds up,
its change in speed can
look like this.

46. Eg.
• A motorcycle move linier with velocity 60
km/hours. Calculate the distance travelled by
motorcycle after 2 hour and ½ hour! And make a
graph!
hour distance
1 -> 60 km/h
2 -> 2 x 60 = 120 km/h
½ -> ½ x 60 = 30 km/h

47. Learning Checkpoint
This graph shows several
stages of motion:
• Stage 1: 100 m in 10 s
• Stage 2: 50 m in 10 s
• Stage 3: 150 m in 20 s
Calculate the speed as indicated by each
of the colors.
Calculate the average speed.
What is the total distance?
What is the displacement?

48. Solution
Stage 1: S= d/ t
100 m/ 10 s= 10 m/s
Stage 2: S= d/t
50 m/ 10 s= 5 m/s
Stage 3: S= d/t
150 m/ 20 s= 7.5 m/s
Ave Speed= Tot d/ Tot t
300 m/ 40 s= 7.5 m/s
Distance = 300 meters
Displacement = 0 meters

49. Consider the following position-time curve.
Graphical Analysis of 1-D Motion
slope of
curve is: RUN
RISE
m =
12
12
t-t
x-x
=
t
x
∆
∆
=
Slope of a P-t
curve at any time
is object’s v at
that time.
time (s)
position(m)
0
5
10
15
0 1 2 3 4 5 6 7

50. Analysing motion graph
15
3 9
Displacement (m)
Time (s)
What is the displacement of the
Object after 3 seconds?
What is the velocity during :
- the first 3 seconds
- the next 3 seconds?
Displacement = 15 m
Velocity : the first 3 s = 5 m/s
the next 3 s = 0

51. Find object’s velocity at
t = 0 to 3.0 s and at t = 6.0
to 7.0 s.
s0-s3
m0-m15
=
t
x
v
∆
∆
=

t
x
v
∆
∆
=

s6-s7
m15-m0
=
( )→=
s
m
5
( )←=
s
m
15-
(–) sign indicates that the object is moving
opposite to how it started
(which we assumed was the (+) direction).
time (s)
position(m)
0
5
10
15
0 1 2 3 4 5 6 7

52. Analysing motion graphs.
Time (s)
Displacement (m)
10 20 30 40 50 60
120
100
80
60
40
20
What is the displacement
after 25 seconds?
What is the velocity during:
- the first 25 s?
- the next 15 s?

53. A particle in a magnetic field moves as follows:
Find the velocity for each part of the motion

54. Velocity-time graph
• A velocity-time graph shows how the velocity
of an object changes with time.
• The gradient of a velocity-time graph
represents the acceleration of the object.
• The area under a velocity-time graph
represents the distance traveled by the
object.

55. Examples
Velocity (m/s)
Time (s)
A B
C
15
20 50 60O
What is the acceleration of the car during
the part of the journey represented by:
- OA - AB - BC
What is the total distance traveled by the
Car?
Calculate the average velocity of the car
for its whole journey.

56. Several examples of velocity-time graph
• Regular / uniform linier motion
Velocity (m/s)
0 Time (s)
Uniform velocity – zero acceleration

57. Accelerated dynamic linier motion
Velocity (m/s)
Time (s)0
Uniform acceleration

58. Velocity (m/s)
Time (s)
Increasing acceleration

59. Decelerated dynamic linier motion
Velocity (m/s)
Time (s)
Uniform deceleration

60. Velocity (m/s)
Time (s)
Decreasing acceleration

61. Decreasing deceleration
Velocity (m/s)
Time (s)

62. Thank you
See you next
tomorrow