1. Motion

2. Motion Object changes position over time compared to a reference point
Object that appears to stay in place
Reference direction
Description of the direction of motion

3. Reference point and direction
Examples include: mountains, buildings, trees, non moving objects
Directions are usually describe as North, South, East, West, up, down, forward, backward

4. Describing Reference Direction
Describing can be positive or negative. A plus sign (+) means the direction from the reference point is in the reference direction. Words: toward, to the left, to the right A minus (-) sign means the direction is opposite to the reference direction Words: away from, backwards

5. Position is a vector
A vector is a quantity that has both size and direction. A vector is the position of an object and can be represented by an arrow.

6. Displacement
Displacement is the difference between the initial position and the final position of an object. Sometimes you can use the Pythagorean’s Theorem to solve for this.

7. Speed Rate at which an object moves
Depends on time taken and distance traveled

8. Changing Speed
Constant speed is when an object travels the same distance each second. EXAMPLE: A car on the freeway with cruise control on. Instantaneous speed is the speed at a specific instant in time. EXAMPLE: When a car comes to a stop sign and then starts up again.

9. Speed
Total distance
Average speed=
Units are in meter per second, miles per hour. Always a distance per time.
Total time

10. Speed Equation
Triangle method – this method allows you to see all three different equations in order to solve for speed or distance or time

11. What is the average speed if you take .5 hr to walk 4000m?
Example Problem 1
What is the average speed if you take .5 hr to walk 4000m?

12. Example Problem 2
If average speed of a car is 100km/hr, how long will it take the car to travel 715 km?

13. Velocity Rate of change of an object’s position
Speed of an object in a particular direction
Always includes reference direction
Velocity changes as speed or direction changes

14. Answer Self Check question
Pg 110
Which of the following are examples of velocity?
25m/s forward 2)1500 km/h
3) 55 m/h ) all of the above

15. Combining Velocities
Combine two velocities in same direction by adding for resultant velocity
Combine two velocities with opposite direction by subtracting the smaller velocity from the larger velocity for the resultant velocity.
Resultant Velocity is in the direction of the larger velocity

16. Final velocity – starting velocity Time it takes to change velocity
Acceleration
Rate at which velocity changes
Tells you how fast velocity changes
Acceleration =
Final velocity – starting velocity
Time it takes to change velocity

17. Positive and Negative Acceleration
Positive acceleration is when acceleration is increasing
Negative acceleration or deceleration is when acceleration is decreasing
Note: a change in direction is acceleration even if there is no change in speed