1. Speed, Velocity and Acceleration
Speed, velocity and acceleration describe how an objects position and motion change through time.
Rates measure change in something over a length of time.

2. What is speed?
Speed -
A measure of the distance an object travels per unit of time.

3. Increasing an object’s speed
By increasing the distance the object travels in the same time. Or
By decreasing the time it takes for an object to travel the same distance.

4. Calculating Speed S= d t Distance meter m kilometer km Time seconds s
Speed (S) = distance object travels
time it takes to travel distance
S= d t
Measuring
Unit
Abbreviation
Distance
meter m
kilometer km
Time
seconds s
hours hr

5. Calculating Speed
If you know any two of the variables, you can calculate the missing variable.

6. Directions STEP 1 STEP 2 STEP 3 STEP 4 Write the correct formula
Plug in the information that you are given
STEP 2
STEP 3
Solve the answer
STEP 4
Add your units

7. PRACTICE S= 4 meters/second
Calculate the speed of a car going 80 meters in 20 seconds.
S= D T
S=80 meters
20 seconds
S= 4 meters/second

8. PRACTICE S=2.5 meters/second
A girl runs 25 meters in 10 seconds. What is her speed?
S= D T
S=25 meters
10 seconds
S=2.5 meters/second

9. Constant Speed
The rate of change of position in which the same distance is traveled each second.

10. Average speed = total distance total time traveled
S= td tt

11. Solve the average speed: Melissa shot a model rocket 360 m into the air. It took the rocket 4s to fly that far. What was the average speed of the rocket?
S= td tt
S=360 meter
4 seconds
S=90 meters/second

12. If Jessica ran 5 meters the first second, 8 meters the next second, and 8 meters the third second to her house. What was her average speed?
S= td tt
S=5 meters + 8 meters + 8 meters = 21 m
3 seconds s
S=7 meters/second

13. Speed at a specific instant in time.
Instantaneous Speed
Speed at a specific instant in time.
When driving in a car you often change speed. What object in the car tells you your instantaneous speed?
Speedometer