1. 3.1 Notes, Part B

2. Today’s Objectives Calculate the average speed of an object. Explain the difference between speed and velocity.

3. Speed Distance an object travels per unit of time –Distance in meters –Time in second Scalar quantity refers to "how fast an object is moving.“ Speed = Distance time = d t

4. Speed changing

5. Speed SI unit for speed is m/s m/s

6. Average speed = total distance traveled divided by total travel time –Km/hour Instantaneous speed = speed at a single instant of time –Speedometer measures this

7. Example While on vacation, Lisa Carr traveled a total distance of 440 miles. Her trip took 8 hours. What was her average speed? To compute her average speed, we simply divide the distance of travel by the time of travel.

8. Velocity Speed and direction Vector quantity refers to "the rate at which an object changes its position.“ –I traveled south at 60 mi/h to get to school Velocity changes if … –You change speed –You change direction

9. Average velocity Different from average speed

10. Example 1 Physics Teacher again, walked 12 m in 24 seconds Displacement = 0 m Average speed = 0.50 m/s Average velocity = 0 m/s

11. Example 2 Cross-country skier again Distance = 420 m Displacement = 140 m, right Average speed = 140 m/min Avg. velocity = 46.7 m/min, right

12. Example 3 Football coach again, Distance = 95 yds Displacement = 55 yds, left Average speed = 9.5 yds/min Avg. velocity = 5.5 yds /min, left

13. In-class Assignment/Homework 3.1 Reinforcement & Enrichment WKT

14. Today’s Objectives Write equations for the displacement and velocity of an object over time. Recognize and draw graphs of an objects displacement and velocity verses time.