1. Definition : distance traveled per unit time
Speed and Velocity 1
Kinematics 2
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Speed
Definition : distance traveled per unit time
Unit : metre per second (m s-1)
Nature : scalar (with magnitude only)

2. Definition : displacement traveled per unit time
Speed and Velocity 2
Kinematics 2
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Velocity
Definition : displacement traveled per unit time
Unit : metre per second (m s-1)
Nature : vector (with magnitude and direction)

3. Concepts of speed and velocity
Kinematics 2
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Concepts of speed and velocity
Daily Use of Terms and Description
Different kinds of motion
Photo
Difference between speed and velocity
Different descriptions of motions
e.g. small velocity but high speed
Example
Calculation

4. Definition : change in velocity per unit time
Acceleration 1
Kinematics 2
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Acceleration
Definition : change in velocity per unit time
Unit : metre per second squared (m s-2)
Nature : vector (with magnitude and direction)
Accelerating motion and decelerating motion
Diagram
Calculation

5. Time Duration between 2 dots : 0.02s
Acceleration 2
Kinematics 2
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Ticker Timer
Frequency : 50 Hz
Time Duration between 2 dots : 0.02s
Different patterns of dots
Diagram
Calculation of velocity/acceleration from dots
Calculation
Tape chart
Diagram

6. Frequency depends on the machine
Acceleration 3
Kinematics 2
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Stroboscope
Frequency depends on the machine
Time Duration between 2 images : calculated from the frequency
Calculation of speed/velocity/acceleration from images
Calculation

7. Three different kinds of time-graphs
Kinematics 2
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Time graphs
Three different kinds of time-graphs
Linear motions only
Direction shown by the sign of the data
Displacement vs time graphs (s vs t graphs)
Velocity vs time graphs (v vs t graphs)
Acceleration vs time graphs (a vs t graphs)

8. Displacement vs time graphs
Kinematics 2
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Displacement vs time graphs
Constant displacement situation
Constant velocity situation
Constant acceleration situation
The graphs’ slope and velocity
Graph

9. Velocity vs time graphs
Kinematics 2
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Velocity vs time graphs
Constant displacement situation
Constant velocity situation
Constant acceleration situation
The graphs’ slope and acceleration
Graph
The graphs’ area and displacement
Graph

10. Acceleration vs time graphs
Kinematics 2
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Acceleration vs time graphs
Constant displacement situation
Constant velocity situation
Constant acceleration situation
The graphs’ area and change in velocity
Graph

11. Constant acceleration situation only
Equations of Motion 1
Kinematics 2
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Equations of motion
Linear motions only
Constant acceleration situation only
Direction given by the signs of the values
Introduction of parameters involved
Diagram

12. Example 3 (Turning point)
Equations of Motion 2
Kinematics 2
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Equations of motion
Example 1
Calculation
Example 2
Calculation
Example 3 (Turning point)
Calculation

13. Acceleration due to gravity (g) = 10 m s-2
Equations of Motion 3
Kinematics 2
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Projectile motion
Acceleration due to gravity (g) = 10 m s-2
It is always pointing downwards
Projectile Motion
Calculation
Example
Calculation

14. END of Kinematics 2

15. Different kinds of motion
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Speed and Velocity 3
Kinematics 2
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Different kinds of motion
Constant speed (slow)
Constant speed (fast)
Moving slower and slower
Moving faster and faster

16. Back to Speed and Velocity 3 Kinematics 2 Click Back to
Consider the motion of the person in the following diagram.
He takes 6 seconds to travel 3 m due east from A to B.
He takes 4 seconds to travel 4 m due north from B to C.
4 m C
Average speed from A to C
North
36.9°
Average velocity from A to C
3 m A B

17. Back to Acceleration 1 Kinematics 2 Click Back to Accelerating motion
Decelerating motion

18. Back to Acceleration 1 Kinematics 2 Click Back to
An object changes its velocity from 2 m s-1 to 6 m s-1 in 4 seconds. What is its acceleration?
2 m s-1
6 m s-1

19. Back to Acceleration 2 Kinematics 2 Click Back to Starting point
Different pattern of dots
Small constant velocity
Large constant velocity
Accelerating motion
Decelerating motion

20. Back to Acceleration 2 Kinematics 2 Click Back to A B C D
A paper tape is shown in the following diagram.
2 cm
5 cm
8 cm A B C D
Average velocity (from A to B)
Average velocity (from C to D)
Acceleration
Average velocity (whole path)
This is so-called the 2-tick interval.

21. Back to Acceleration 2 Kinematics 2 Click Back to velocity time
Cut the following tape according to the dotted lines.
velocity
Arrange the tapes (2-tick interval) side by side
Join the top of each tape
Add x-axis (time) and y-axis (velocity)
Suitable scale should be chosen for x-axis (time) and y-axis (velocity)
We can choose different intervals
time

22. Back to Acceleration 3 Kinematics 2 Click Back to A B C D E
The images of an object sliding down an inclined plane :
2 cm
5 cm
8 cm
11 cm C B A D E
Frequency of stroboscope = 10 Hz
Time between successive images
Average velocity (from A to B)
Average velocity (from C to D)
Acceleration

23. Slope of s-t graph = Velocity at that time Back to Time Graphs 2
Kinematics 2
Click Back to
s (m)
t (s) 3 2
s (m)
t (s) 4 2
Slope = 0 Velocity = 0 m s-1
Slope = 2 Velocity = 2 m s-1
Constant displacement
Constant velocity
s (m)
t (s)
Slope is increasing Velocity is increasing
Slope of s-t graph
= Velocity at that time
Constant acceleration

24. =Acceleration at that time
Back to
Time Graphs 3
Kinematics 2
Click Back to
v (m s-1)
t (s) 2
v (m s-1)
t (s) 4 2
Slope = 0 Acceleration = 0 m s-2
Slope = 0 Acceleration = 0 m s-2
Constant displacement
Constant velocity
v (m s-1)
t (s) 2 4
Slope = 2 Acceleration = 0 m s-2
Slope of v-t graph
=Acceleration at that time
Constant acceleration

25. = Displacement traveled
Back to
Time Graphs 3
Kinematics 2
Click Back to 2
v (m s-1)
t (s) 4 2
v (m s-1)
t (s)
Area = 0 Displacement traveled = 0 m
Area = 8 Displacement traveled = 8 m
Constant displacement
Constant velocity
v (m s-1)
t (s) 2 4
Area = 8 Displacement traveled = 4 m
Area of v-t graph
= Displacement traveled
Constant acceleration

26. Area of a-t graph = Change in velocity Back to Time Graphs 4
Kinematics 2
Click Back to
a (m s-2)
t (s) 2
a (m s-2)
t (s) 2
Area = 0
Change in
velocity = 0 m s-1
Area = 0
Change in velocity = 0 m s-1
Constant displacement
Constant velocity
a (m s-2)
t (s) 2 4
Area = 8
Change in velocity = 8 m s-1
Area of a-t graph
= Change in velocity
Constant acceleration

27. Kinematics 2 Back to Equations of Motion 1 Equations of Motion :
Click Back to
u = initial velocity
v = initial velocity
s = displacement traveled
a = acceleration
t = time required
Equations of Motion :
(take forward direction as +ve)

28. Back to Equations of Motion 2 Kinematics 2 Click Back to
u = 2 m s-1
v = 8 m s-1
s = ?
a = ?
t = 4 sec
+ve acceleration means the object is accelerating
+ve displacement means forward displacement

29. Back to Equations of Motion 2 Kinematics 2 Click Back to
u = 8 m s-1
v = 2 m s-1
s = 10 m
a = ?
t = ?
-ve acceleration means the object is decelerating

30. Back to Equations of Motion Kinematics 2 Click Back to
u = 8 m s-1
v = ?
s = ?
a = -2 m s-1
t = 6 s
-ve final velocity means the object is moving backwards at that time. Where is the “turning point”?
At t = 4 s, the object stops momentarily.

31. Back to Equations of Motion 3 Kinematics 2 Click Back to a = -10 m s-2
-ve acceleration means it is pointing downwards (upward direction)

32. Back to Equations of Motion 3 Kinematics 2 Click Back to u = 50 m s-1
v = 10 m s-1
a = -10 m s-2
s = ?
t = ?
-ve acceleration means it is pointing downwards (upward direction)
+ve displacement means upward displacement