1. Measuring Motion Vocabulary: Motion, Speed, Velocity and Acceleration
Chapter 1 section 1 pages 4-9
Vocabulary:
Motion, Speed, Velocity
and Acceleration

2. Motion Reference Point: Something that appears to stay in place
When an object changes position
over time relative to a reference point,
the object is in motion.
Reference Point:
Something that
appears
to stay in place

3. Speed Speed is the rate of motion, often
expressed as distance traveled
per unit of time.
Speed
Page 5
Total Distance
average speed =
Total Time
Your driving up with the family and you’ve been on the road for 2 hours.
You’ve traveled130 miles. What is your average speed?
Answer: 65 miles / hour

4. Compare actual speed to average speed. Use the graph below to
Speed you are traveling
at that instance. This varies
due to traffic, weather conditions,
the need for a quick pit stop, etc…..
Compare actual speed to
average speed. Use
the graph below to
explain the difference.
Average speed:
Total distance you’ve
traveled ÷ the total time
you’ve traveled
A Graph Showing Speed

5. Graphing Speed: Distance vs. Time Graphs
Speed = Slope = Rise/Run
Rise

6. Graphing Speed: Distance vs. Time Graphs
Speed = Slope = Rise/Run
Rise=?
600 km
3 h

7. Graphing Speed: Distance vs. Time Graphs
Speed = Slope = Rise/Run
Rise=?
600 m
3 minutes
Rise/Run = 600 km/3 hr
= 200 km/hr

8. Different Slopes Slope = Rise/Run = 0 km/1 hr = 0 km/hr Rise = 2 km
Run = 1 hr
Rise = 0 km
Run = 1 hr
Slope = Rise/Run
= 2 km/1 hr
= 2 km/hr
Rise = 1 km
Run = 1 hr
Slope = Rise/Run
= 1 km/1 hr
= 1 km/hr

9. Question
Below is a distance vs. time graph for 3 runners. Who is the fastest?
Leroy is the fastest. He completed the race in 3 hours

10. Calculating
Average
Speed

11. When objects will move at a steady rate with a constant speed, the object will cover the same distance every regular interval of time.
For instance, a cross-country runner might be running with a constant speed of 6 m/s in a straight line for several minutes. If her speed is constant, then the distance traveled every second is the same. The runner would cover a distance of 6 meters every second.
If we could measure her position (distance from an arbitrary starting point) each second, then we would note that the position would be changing by 6 meters each second. This would be in stark contrast to an object that is changing its speed. An object with a changing speed would be moving a different distance each second. The data tables below depict objects with constant and changing speed.

12. The speed of an object in a particular direction
Velocity p.6
The speed of an object in
a particular direction
You and a friend raced back to your house. You both traveled at the same speed, but you got there first. Why?
You took the direct route “straight line” to the house.
When speed and direction remains the same, it’s known
as “constant velocity.”

13. By changing Speed and/or Direction
What are the 2 ways that velocity can change?
By changing Speed and/or Direction
p. 6

14. Accelerationp. 7 Pay attention here people! Rate at which velocity
changes
Accelerationp. 7
Pay
attention
here
people!
Acceleration actually means the rate at which something
speeds up or
slows down or changes direction!!

15. Types of acceleration Increasing speed Decreasing speed
Example: Car speeds up at green light
Decreasing speed
Example: Car slows down at stop light
Changing Direction
Example: Car takes turn (can be at constant speed)
screeeeech

16. Negative acceleration Positive accelerationOr
Deceleration
(decreasing speed)
Positive acceleration or
Increasing speed
Come up to the smart board and
identify where positive acceleration
and deceleration will probably occur.

17. Acceleration only occurs when an object is increasing in speed.
False
True or false:
Acceleration only occurs when an
object is increasing in speed.
Positive Acceleration
A Graph Showing Acceleration
Negative acceleration or deceleration
P. 8

18. Question
How can a car be accelerating if its speed is a constant 65 km/h?
If it is changing directions it is accelerating

19. Graphing Acceleration
Can use 2 kinds of graphs
Speed vs. time
Distance vs. time

20. Graphing Acceleration: Speed vs. Time Graphs
Speed is increasing with time = accelerating
Line is straight = acceleration is constant

21. Graphing Acceleration: Speed vs. Time Graphs
Rise = 4 m/s
Run = 2 s
In Speed vs. Time graphs:
Acceleration = Rise/Run
= 4 m/s ÷ 2 s = 2 m/s2

22. Graphing Acceleration: Distance vs. Time Graphs
On Distance vs. Time graphs a curved line means the object is accelerating.
Curved line also means your speed is increasing. Remember slope = speed.

23. Centripetal Acceleration
Acceleration that occurs in a circular motion
p. 9

24. Section Summary p. 9
An object is in motion if it changes position over time
in relation to a reference point.
Speed is the distance traveled by an object divided
(speed = distance ÷ time) by the time the object
takes to travel that distance.
Velocity is speed in a given direction.
Acceleration is the rate at which velocity changes.
An object can accelerate by changing speed, direction, or both.
Speed can be represented on a graph of distance versus time.
Acceleration can be represented by; graphing velocity versus time.
Acceleration that occurs in circular motion is known as centripetal acceleration.

25. See you at the finish line!