2. Warm-up This past weekend I went to Ocean City, NJ which was a 60 mile drive and returned on Monday.” How far did I travel this weekend?”

3. MECHANICS MECHANICS – The branch of Physics that deals with the motion of objects and the forces that change this motion. Kinematics – The motion part of Mechanics. Dynamics – The force part of Mechanics. 1-D MOTION

4. POSITION – The separation between an object and a reference point. DISTANCE (d) – The length of the path an object took as it moved between positions. SCALAR QUANTITY SCALAR QUANTITY – A measurement with magnitude but no direction. SIZE

5. DISPLACEMENT (d) – The straight line distance and direction between an object’s starting position and its stopping position. VECTOR QUANTITY VECTOR QUANTITY – A measurement that has magnitude and direction. Represented by bold face variable (text book) or an arrow above the variable. (Notes)

6. A. What is their final position with respect to Juniors initial position? B. What is Larry’s total displacement? C. What distance did each veggie travel? PRACTICE L J B 25.0 m 8.0 m 12.0 m Larry the Cucumber walks 25.0 m, east to visit Junior. They then walk 8.0m, west to visit Bob. They then all walk 12.0m, east to go to Krispy Kreme. If Larry now travels back home, what is his displacement now?

7. SPEED – The RATE of distance. SCALAR

8. VELOCITY – The RATE of displacement. VECTOR

9. A soldier marches 18 paces, east in 7 seconds, stops for 5 seconds and then marches 12 more paces east in 6 seconds. What is the soldiers speed and velocity for the whole trip? The soldier now moves 25 paces, west. If this takes 10.0 more seconds, what is the soldiers speed and velocity for the whole trip? (From the beginning) The soldier now marches 5 paces, west in 5.0 seconds. What is the soldiers speed and velocity for the whole trip now? (From the beginning)

10. Instantaneous Speed/Velocity – The speed/velocity at any moment of time. Constant Speed/Velocity – A speed/velocity that is not changing. Average Speed/Velocity – The constant speed/velocity that would need to be maintained to get the same end distance/displacement in the same time.

11. 1V 3V5V7V 9V 11V Bob does the following: 1V/s for 3 seconds, then rests for 3 seconds, then 2 V/s for 3 seconds

12. 1V 3V5V7V 9V 11V Bob does the following: 3V/s for 4 seconds, then rests for 2 seconds, then -2 V/s for 4 seconds

13. 1. A sprinter runs 100.0 m, west, in 9.70 seconds. A. What is the sprinter’s average velocity? B. At this velocity, how long would it take to run 1609 m (1mile)? C. At this velocity how far would the sprinter travel in 1.00 hour?

14. 2. A swimmer dives into a pool and swims 50.0 m, east in 8.00 seconds and then turns around and swims 30.0 m west in 5.00 seconds. A. What is the average speed of the swimmer? B. What is the average velocity of the swimmer? 50.0 m 30.0 m

15. 3. A car travels 100 miles, east in 5.0 hours, then travels 75 miles, west in another 5 hours and then does one more thing that takes 5 more hours. If the car’s average velocity for the whole trip is 25 miles/hour, east, what displacement did the car have in the third part of the trip?

16. Acceleration – The RATE of velocity change. GALILEO: “when an object gains or loses equal increments of speed during equal increments of time.” UNITS? m s s VECTOR

17. Practice Suppose a car is moving in a straight line steadily increases its speed each second, first from 35 to 40 mph, then 40 to 45 mph, then 45 to 50 mph. What is its acceleration?

18. Practice #2 In 5 seconds a car moving in a straight line increases its speed from 50 mph to 65 mph, while a truck goes from rest to 15 mph in a straight line. Which undergoes greater acceleration? What is the acceleration of each vehicle?

19. Concept Review: 1. What does it mean if an object has a positive acceleration? 2. What does it mean if an object has a negative acceleration? 3. What does it mean if an object has zero acceleration? 4. Is it possible for an object to have zero velocity and a non-zero acceleration? Explain. 5. How are velocity and acceleration related?