2. Negative 10 Miles per Hour? 1-1-2 Velocity and Speed

3. Velocity vs. Speed VELOCITY –change in DISPLACEMENT occurring over time –Includes both MAGNITUDE and DIRECTION VECTOR SPEED –change in DISTANCE occurring over time –Inclues ONLY MAGNITUDE SCALAR

4. Average Velocity/Speed Equations average speed or velocity distance or displacement time average speed or velocity two velocities or speeds average speed total distance total time

5. Example #1 Jim gets on his bike and rides 300 meters west in 60 seconds. What is his average velocity? What is his average speed? v = d / t v = 300 m / 60 s v= 5 m/s WEST v = d / t v = 300 m / 60 s v= 5 m/s v = d / t v = -300 m / 60 s v = -5 m/s

6. Example #2 Sally gets up one morning and decides to take a three mile walk. She completes the first mile in 8.0 minutes, the second mile in 8.5 minutes, and the third mile in 9.0 minutes. What is her average speed?

7. Example #3 A car’s speed changes from 20 meters per second to 10 meters per second. What is its average speed?

8. How Graphs Show Velocity and Speed What is happening in this graph? Motionless Object CONSTANT ZERO SLOPE

9. How Graphs Show Velocity and Speed What is happening in this graph? CONSTANT POSITIVE SLOPE Moving with CONSTANT positive velocity

10. How Graphs Show Velocity and Speed What is happening in this graph? INCREASING SLOPE Moving with INCREASING velocity

11. Find displacement Using v-t Graphs Find distance traveled What can we DO with a v-t graph? Find average velocity How do you use the v-t graph to find AVERAGE VELOCITY? How do you use the v-t graph to find DISTANCE TRAVELED? How do you use the v-t graph to find DISPLACEMENT? Area under the graph Area on TOP and BOTTOM both considered POSITIVE Area under the graph Area on TOP = POSITIVE Area on BOTTOM = NEGATIVE