MOTION
Continued
• Complete the following table.
Speed
Distance
Time
A
80 cm
4s
B
0.5 cm
0.2 s
C
500 km
2.5 h
D
15 cm
60 s
4 m/s
E
8.5 s
0.8 km/h
F
4h
9 m/s
45 m
G
800 cm/s
6400 cm
H
Questions
• Change:
– 8 km to metres
– 90 cm to metres
– 180 minutes to hours
– 0.5 h to seconds.
– 7200 seconds to hours
• A bullet travels 2200 m in 4 seconds. What is
the average speed of the bullet?
• A cyclist rides at a speed of 10 m s -1 for 45
seconds. What distance does she travel?
• A car travels at an average speed of 70 km h -1
on a journey. What time will it take to travel a
distance of 350 km?
Practical applications…….
• The diagram shows how an
echosounder is used to
find the depth of water
beneath a ship.
– A pulse sound which travels
at a speed of 1800 m/s, is
sent into the water. The
reflected sound is detected
0.05 s later. How deep is
the water below the ship?
Distance-Time Graphs
• Distance-Time Graphs show the time taken to
travel a certain distance. The slope (gradient)
of the graph gives information about the
speed of the object.
Continued……..
• A straight line represents a constant speed.
• A horizontal line represents zero speed. The
object is not moving.
• The steeper the slope, the greater the speed.
• When a distance-time graph is not a straight
line, the object is changing speed.
• The graph shows a journey
in a car. During which
section of the journey
was the car travelling at
greatest speed? Why?