1. Chapter 9- Motion Speed The distance something travels compared to the amount of time it takes How fast something is moving YouTube - Thrust SSC Supersonic Boom YouTube - Thrust SSC | SSC | Thrust SSC : Breaking The Sound Barrier YouTube - Supersonic Flight, Sonic Booms

2. Three Ways to Measure Speed: 1.Constant- stays the same ex. cruise control 2. Instantaneous- speed at a specific point in time ex. radar gun

3. 3. Average- speed you travel during a set amount of time

4. Formula: Speed = Distance Time Speed Practice Problems 1.If the earth spins on its axis at 1100 miles/hour, how far will it spin after 12 hours?

5. 2. The earth travels at 68,000 miles/hour as it moves around the sun. How many miles does the earth travel in one day around the sun?

6. 3. You drive 200 miles in 3 hours. After lunch you travel 150 miles in an hour and a half. What was your average speed for the trip?

7. Speed Graph

8. Velocity vs. Speed Velocity Describes both speed and DIRECTION of an object Velocity Practice Problem: 4. Calculate the average velocity of a dancer who moves 5 m toward the left of the stage over the course of 15 s. YouTube - They Might Be Giants - Speed and Velocity w/ Marty Beller

9. Acceleration -a change in speed (velocity) Can be positive (speed up) Can be negative (slow down)

10. Formula: acceleration = S f – S i t S f - speed final (end) S i - speed initial (beginning) t- time Acceleration Practice Problem: Calculate the acceleration of a bus whose speed changes from 6 m/s to 12 m/s over a period of 3 s.