This power point is for the children studying year 7. I hope they enjoy if you share with them.

1. Speed
By Dr. Keja
Senior Researcher Fellow
City University London

2. Objectives
• Sense of speed
• How to calculate speed
• Understand the mean speed

3. Sense of Speed
58 km
in one
hour
360 km in one hour
920 Km in one hour
28,968 in one hour

4. Define speed
• Speed is to tell how ____________ an object is
moving.
• To calculate the speed __________ and _______
are needed.
• Choose from the following:
• distance, time, fast
fast
timedistance

5. Calculating speed
Speed=
Distance
Time

6. Remember the triangle of speed
d
s t

7. Do you know?
• Which has the highest speed?
Light
– 300000000 m/s in vacuum
– 200000000 m/s in glass

8. Unit for speed for practical purpose
distance time speed of unit
meter sec m/s
miles hour
Km Hour
Miles/hour
Km/hour

9. Units
UK
Miles/hour
US
Km/hour
d
s t

12. Usain Bolt record

13. Q1. Bolt ran 100 m in 9.58 sec. Calculate the speed of
Bolt.
• Distance = 100 m
• Time = 9.58 sec
d
s t
speed =
distance
time
=
100 𝑚
9.58 𝑠𝑒𝑐
= 10.43 𝑚/𝑠

14. True or False?
• Jey was driving in an area where the speed
limit was 50 Km/hour. She travels 10 Km in 10
minutes. She has broken the speed limit.
Object/Person Total distance Total time Average speed unit
Jey 60 Km 1 hour
10 Km 10 Minutes
60 Km 60 Minutes
60 Km/h

15. Complete Q2-Q5
Object Distance Time Speed
Q1 Flight 2 Km 3 secs
Q2 Leopard 232 Km 4 hours
Q3
Sound in
water
14820 m 10 second
Q4 Sound in air 3430 m 10 second

16. Q2. A flight travels 2Km in 3 sec. Calculate the speed
of the flight.
• Distance = 2 Km
• Time = 3 sec
• Speed =
d
s t
𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒
𝑡𝑖𝑚𝑒
2 𝑘𝑚
3 𝑠𝑒𝑐
0.66 𝐾𝑚/𝑠

17. Complete Q2-Q5
Object Distance Time Speed
Q1 Flight 2 Km 3 secs
Q2 Leopard 232 Km 4 hours
Q3
Sound in
water
14820 m 10 second
Q4 Sound in air 3430 m 10 second
0.666 Km/s
58 Km/h
1482 m/s
343 m/s

18. Summary
• Speed=
𝐷𝑖𝑠𝑡𝑎𝑛𝑐𝑒
𝑇𝑖𝑚𝑒
• Speed can be used to calculate the distance
travelled by an object or person in a given
time.
d
s t