1) Speed is defined as the distance travelled per unit time and is a scalar quantity measured in meters per second (m/s). Uniform speed means the change in distance with time is constant. 2) Velocity is the change in displacement with time and is a vector quantity. Uniform velocity means the change in displacement is equal over equal time intervals. 3) A distance-time graph plots distance on the y-axis against time on the x-axis, while a displacement-time graph plots displacement versus time.

1. LINEAR MOT
SPEED & VEL

2. SPEED & VELOCITY
SS1PHY
LESSON CONTENTS
 THE CONCEPT OF DISTANCE
SPEED & VELOCITY
 UNIFORM SPPED & VELOCITY
 CALCULATION ON SPEED &
VELOCITY
 DISTANCE-TIME GRAPH
DISPLACEMENT-TIME GRAPH

3. CONCEPT OF DISTANCE
SS1PHYS
Distance can also be defined as the length of
space covered by an object when it changes position
from one point to another. Distance is a scalar quantity
is not specified and it S.I. unit is the metre with a
symbol of (m).
Speed: Speed is defined as the distance travelled per
unit time. It is also the time rate of change of distance.
It is a scalar quantity & it is given as;
The S.I unit of speed is metre per second m/s)
Uniform speed or constant speed: A body is said to
undergo uniform speed when its change of distance
with time is constant. In other words, it is when a body
covers equal distance in equal time interval.

4. Velocity: Velocity can be defined as the change
in displacement with time. It is a vector quantity &
given as
Uniform or Constant velocity: A body is said to
undergo uniform velocity when it change in
displacement is equal to rate of change time. It means
the body displaces equal amount in equal time
intervals.
SS1PHYS

5. SS1PHYS
Distance/Displacement- time graph
This is a graph with distance/ Displacement on
the vertical axis & time on the horizontal axis. By
measuring distance at a known time interval & plot
the distance on the vertical axis against time on the
horizontal it gives a distance-time graph.
If displacement at known time interval is plotted on
the vertical against time on the horizontal it gives a
displacement- time graph.
(diagram of displacement-time )

6. SS1PHYS

7. Retardation or Deceleration
SS1PHYS
Retardation is defined as the time rate of
decrease of velocity. Retardation is also called
deceleration & is the negative of acceleration.
Uniform Acceleration: A body is said to undergo
uniform acceleration when the time rate of increase in
velocity is constant. It means the velocity increases by
equal amount in equal time intervals.

8. Ex1. What is the distance covered by a car
which travels with a constant speed of 20.8m/s for
30s.
Ex2 A car travels 8km due east and makes a U-turn
back to travel a further distance 5km. Calculate (a)
Distance covered (b) Its displacement.
Ex3. During an Olympics game, an athlete ran a
200m in 15.23s. What is the average speed?
Ex4. Convert the following to m/s .
(a)36km/h
(b) 72km/h
(c) 108km/h
(d)240km/h
EXAMPLES & CLASSWORK

9. 1. The average speed of a car is 45mins in
35km/h. How far has it travel in 45mins?
2. A car travels uniformly from 5m/s to 13m/s for 5s.
What is the acceleration of the car?
ASSIGNMENT

10. THANK YOU