2. Speed
 Speed = Distance ÷ Time
D_
S T
Example: A car travels 300km in 6 hours.
What is the speed of the car?

3. Answer:
 Speed = distance ÷ time
 Speed = 300km ÷ 6 hours
 Speed = 50km/hr

4. More practice
 1. How far can a plane travel if it flies
800km/hr for 9 hours?
 2. How long does it take a ship to go
500 km if it travels at a speed of
50km/hr?

5. Answer
1. D
S T
D
800 9
800km ▪ 9hrs = 7200km
hr

6. Answer
2. D
S T
500
50 T
500km ÷ 50km = 10 hrs
hr

7. Velocity
 Speed in a given direction.
 What is the velocity of a boat that
travels from St. Peter to Mankato
(10 miles) in 15 minutes?

8. Answer
 Speed = distance ÷ time
 Speed = 10 miles ÷ 15 minutes
 Speed = 0.67 mi/min
 Velocity = 0.67 mi/min South

9. Change your answer to mi/hr!
 0.67mi/min x 60min/hr =
 40 mi/hr

10. Distance-time graphs
 On your paper, graph the following:
 D (m) T (sec)
0 0
5 7
10 14
15 21

12. Was your graph a straight line?
 A distance-time graph which is a
straight line indicates constant
speed.
 In constant speed, the object
does not speed up or slow down.
The acceleration is zero.

13. Graph the following on a distance-
time graph:
 D (m) T (s)
0 0
5 1
20 2
45 3
80 4
125 5

14. 0 1 2 3 4 5

15. Was your graph a curve?
 A graph that curves on a
distance-time graph shows that
the object is accelerating

16. Distance-time graphs
 Describe the motion of the object as
shown in the
graph.
From 0-8 sec,
constant speed:
(25 m/sec);
From 8-12 sec,
no motion;
From 12-16 sec,
acceleration;
From 16-20 sec,
constant speed

17. Speed-time graphs
 Using the distance-time graph from the
last frame, draw a speed time graph. First
fill in the table below:
Average Speed (m/s) Time (sec)
____ 0 to 8
____ 8 to 12
____ 12 to 20
25
0
37.5

18. What does your graph look like?
 Constant speed will be a
horizontal line on a speed time
graph.
 If the speed decreases, the line
will slant down.
 If the speed increases, the line
will slant up.