1. Chapter 1, Section 1 Measuring Motion

2. When an object changes position over time, the object is in motion..

3. Motion can be observed by using a reference point. A reference point is an object that appears to stay in place compared to a moving object. This allows you to tell that the object is in motion Reference point Example: trees, buildings, Earth’s surface

4. Speed is the amount of time it takes you to travel a specific distance. To calculate speed: Average speed= total distance total time The units for speed are : m/s, km/h

5. Objects with speed

6. Velocity is the speed of an object in a particular direction.Velocity must include a direction. (north, south, left, right) To calculate velocity: total distance + direction total time

7. Velocity is only constant if speed and direction do not change. Constant velocity is the motion of a straight line. If there is a change in speed ( 15 m/s to 20 m/s) or direction (east to west), the velocity will change.

8. Rocket changing velocity

9. To combine velocities, it depends on whether the object is traveling in the same direction or different direction. The result is the resultant velocity. Same direction: add velocities together 10 m/s north + 5 m/s north= 15 m/s north Different direction: Subtract velocities 15 m/s west + 10 m/s east= 5 m/s west

10. Acceleration is the rate at which velocity changes. If an object’s speed or direction change, its velocity changes. An increase in velocity= positive acceleration A decrease in velocity= negative acceleration or deceleration

11. Roller coaster have positive and negative acceleration!

12. To calculate acceleration: Average acceleration = final velocity-starting velocity time it takes to change velocity a= Vf- Vi t Units for acceleration= m/s 2

13. W hen observing a graph you can determine if acceleration is positive or negative based upon the slope. It the slope goes upward it is positive acceleration. If the slope goes downward, it is negative acceleration.

14. Centripetal acceleration occurs when an objects travels in circular motion. Example: the Earth rotating!