1. 1.1Motion and Motion Graphs

2. Kinematics Terminology Scalar vs. Vector Scalar: quantities that have only a size, but no direction – ie: distance, speed Vector: quantities that have a size and direction – ie: displacement, velocity

3. Kinematics Terminology Distance ( d ) – the length of the path travelled Position ( d ) – describes the distance and direction from a reference point Displacement ( Δd ) – the change in position of an object

4. Speed and Velocity Average Speed – the total change in distance over an elapsed period of time (m/s) Average Velocity – the change in displacement over an elapsed period of time

5. Speed and Velocity Instantaneous Velocity – the velocity of an object at a specific time

6. Example A jogger takes 25.1 s to run a total distance of 165 m by running 140 m [E] and then 25 m [W]. The displacement is 115 m [E]. (a) Calculate the jogger’s average velocity. (b) Calculate the jogger’s average speed.

7. Position-Time Graphs A straight line represents uniform motion – Positive slope  forward motion – Negative slope  backward motion – Zero slope  stationary

8. A curved line represents non-uniform motion (acceleration) v avg  slope between two points v ist  slope of tangent Position-Time Graphs

9. Example The position–time graph shows the details of how an object moved. Calculate the average velocity during the time interval t=1.0 s to t=2.5 s.

10. Acceleration Uniform Motion – motion at a constant speed in a straight line Non-uniform Motion – the change in an object’s velocity Acceleration – the change in velocity over an elapsed time period

11. Velocity-Time Graphs A straight line represents constant acceleration – Positive slope  acceleration – Negative slope  deceleration – Zero slope  constant velocity (no acceleration)

12. Velocity-Time Graphs A curved line represents non-uniform acceleration – a ave  slope between 2 points – a inst  slope of tangent

13. Homework Read Section 1.1 Questions p. 10 #1-3 p. 15 #1-3 p. 16 #1-2, 4-6