1. Speed
Distance an object travels in one unit of time

2. Examples of Speed 125miles per hour 125m/hr 125mph 20cm/year
20centimeters per year
This car is in motion at a speed of 125 miles per hour.

3. Always includes distance
Speed
Always includes distance
compared to time
Example:
This car can achieve a speed of
125 miles
per
hour.

4. How to calculate speed:
Divide the distance that the object travels by the time that it takes to travel the distance
Distance
Speed = Time

5. Yes, speed =
Distance
divided by
Time OR
Distance
Time

6. Let’s practice:
A cheetah chased an antelope across the field for 1 minute. During that time, he covered 5 kilometers. At what speed did he chase the antelope?
Speed = Distance / Time
Speed = 5km / 1minute
Speed = 5km / min

7. It took an ant 5 seconds to walk 50 mm. At what speed did he walk?
Let’s practice:
It took an ant 5 seconds to walk 50 mm. At what speed did he walk?
Speed = Distance / Time
Speed = 50mm / 5seconds
Speed = 10 mm / sec

8. Let’s practice:
It took a ball 20 seconds to roll 60 meters. At what speed did it roll?
Speed = Distance / Time
Speed = 60meters / 20secs
Speed = 3meters per second

9. Constant Speed
Unchanging speed

10. Average Speed
Since speed is usually not constant, we usually need to find the average speed of a moving object. How do we do that?

11. You need to make some calculations…
Total Distance
Average Speed =
Total Time
Or you could write it this way…
Total Distance
Total Time
Average Speed =

12. Try this:
According to the tables below, which car is traveling at a constant speed?
Motion of Car A
Motion of Car B
Time
(s)
Distance
(m) 1 4 2 9 3 12 21 5 25
Time
(s)
Distance
(m) 1 5 2 10 3 15 4 20 25
Idea from:

13. According to the tables below, what is the average speed of each car?
Try this:
According to the tables below,
what is the average speed of each car?
Motion of Car A
Motion of Car B
Time
(s)
Distance
(m) 1 4 2 9 3 12 21 5 25
Time
(s)
Distance
(m) 1 5 2 10 3 15 4 20 25
Idea from: