Speed for Ms. Trnka's Class

1. Calculating the speed and velocity of an object
Bellwork: Read page 451
Describing Motion and Speed Using Strobe Photos
Which plane is traveling faster? Explain how you
interpreted the pictures.
A: Q Q Q Q Q Q
B: Q Q Q Q

2. Video
Brainpop!
( Distance, rate and time)
Rate = ?

3. What is Speed?
• Speed is a measure of the distance an object
moves in a given amount of time.
• During a typical trip to school, your car will
undergo a series of changes in its speed.

4. Speed
Speed = distance travelled
time taken

5. Speed
Speed = distance travelled
time taken
seconds
meters
Meters per second
(m/s)

6. Speed
Speed = distance travelled
time taken
hours
kilometers
Kilometers per hour
(km/h)

7. Distance traveled?
What if we know the speed of an object
and the time it moved for and need to
calculate the distance traveled?

8. Distance traveled?
What if we know the speed of an object
and the time it moved for and need to
calculate the distance travelled?
Speed = distance
time
distance = speed x time

9. Time?
What if we know the speed and the
distance traveled, how do we calculate
how long (time) the journey took?

10. Time?
What if we know the speed and the
distance travelled, how do we calculate
how long (time) the journey took?
Speed = distance
time
time = distance
speed

11. triangle
s tx
d

12. If the distance is measured in meters
and the time in seconds,
-the speed will be in meters per
second (m/s or m.s-1).
If the distance is in kilometers and the
time in hours,
-the speed will be in kilometers per
hour (km/h)

13. EXAMPLES

14. Usian Bolt ran 100m
in 9.58 seconds, what
was his average
speed?
10.43 m/s

15. Another example
A dog runs at a
speed of 5 m/s
for one minute.
How far does
he run?

16. Another example
A dog runs at a speed
of 5 m/s for one
minute. How far does
he run?
Distance = speed x time
= 5 m/s x 60s = 300
m

17. Another example!
A car travels at 30
km/h and covers a
distance of 900
km. How long did it
take?

18. Another example!
A car travels at 30 km/h
and covers a distance
of 900 km. How long
did it take?
Time = distance/speed
= 900/30 = 30 hours

19. Practice:
Distance, Speed and Time
Speed = distance (in meters)
time (in seconds)
D
TS
1. Laura covers 2000m in 1,000 seconds. What is her speed?
2. How long would it take to run 100 meters if you run at
10m/s?
3. Steve travels at 50m/s for 20s.
S = D/T
= 2000m/1000s
= 2 m/s
T = D/S
= 100m/10m/s
= 10s
D = S x T
= 50m/s x 20s
= 1000m

20. Speed and Velocity: Pg 455
What are the differences between speed
and velocity?

21. What is Velocity?
Speed in a given
direction is called
velocity.
When you know both the
speed and direction of an
object’s motion, you
know the velocity of the
object.

22. Can we change velocity but
not change speed?
The speed of this car
might be constant,
but its velocity is not
constant because the
direction of motion
is always changing.

23. Now you try!
Practice
Problems:
Page 463
# 1-5