2.
Distance and
Displacement
Distance is the measure of the total length of the path
taken during the change of position of an object
Distance is a scalar quantity
Displacement is the measure of the change of position
of an object
Displacement is a vector quantity
3.
Speed and Velocity
Speed is the measure of rate of the distance covered
Speed is a scalar quantity
Distance covered
Speed (m/s) =
(m)
Time taken (s)
Velocity is the measure of rate of displacement of an
object
Velocity is a vector quantity
Displacement
Velocity
Time taken
=
4.
Scalars and Vectors
Scalars are quantities that have a size (or magnitude)
only
Vectors are quantities that have a size and a direction
5.
d
Speed Distance Time
s
t
We can calculate the speed of a moving
object using the equation :
Average Speed
=
Distance covered
Time taken
s
=
d
t
Because distance is measured in metres (m) and time in
seconds (s), the S.I. unit for speed is metres per second
(m/s or m s-1)
Distance covered
Speed (m/s) =
(m)
Time taken (s)
6.
Acceleration
Δv
a
Δt
Acceleration is the rate of change of speed
Acceleration =
Change in
Velocity
Change in Time
Δv
a
= Δt
Because speed is measured in metres per second (m s1) and time in seconds (s), the S.I. unit for acceleration is :
metres per second squared (m/s/s or m s-2)
Change in velocity (m
Acceleration (m s-2)
s-1)
Change in time
=
(s)
7.
Distance – Time graph
Speed – Time graph
Distance (m)
Distance (m)
Time (s)
Time (s)
Speed (m/s)
Speed (m/s)
Time (s)
Distance (m)
Distance (m)
Speed (m/s)
Time (s)
Time (s)
Time (s)
Speed (m/s)
Time (s)
Time (s)
8.
Distance – Time graph
Distance (m)
Time (s)
On a distance time graph, the slope or gradient of the line
represents the speed of the object at the time
Steeper slope Greater gradient Greater speed
No slope gradient = 0 No speed No movement
Curved line change in gradient change in speed
9.
Speed – Time graph
Speed (m/s)
Time (s)
On a speed time graph, the slope or gradient of the line
represents the acceleration of the object at the time
No slope gradient = 0 No acceleration Constant speed
Steeper slope Greater gradient Greater acceleration
On a speed time graph, the area under the graph
represents the distance covered
10.
Velocity - time graphs
• Distance and displacement can be found from a velocity
- time graph by
velocity
+
Area 1
Area 1 + Area 2 = Distance
Area 1 – Area 2 = Displacement
Area 2
time
11.
Distance – Time graph
Speed – Time graph
Distance (m)
Time (s)
Speed (m/s)
Time (s)
12.
d
Speed Distance Time
s
t
We can calculate the speed of a moving
object using the equation :
Average Speed
=
Distance covered
Time taken
s
=
d
t
Because distance is measured in meters (m) and time in
seconds (s), the S.I. unit for speed is meters per second
(m/s or m s-1)
Distance covered
Speed (m/s) =
(m)
Time taken (s)
13.
Δv
Acceleration
a
Δt
Acceleration is the rate of change of speed
Acceleration =
Change in
Speed
Change in
Time
Δv
a
= Δt
Because speed is measured in meters per second (m s1) and time in seconds (s), the S.I. unit for acceleration is :
meters per second squared (m s-1 /s or m s-2)
Change in speed (m
Acceleration (m s-2)
s-1)
Change in time
=
(s)
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