1. Chapter 2 Motion

2. Motion is Relative

3. When we describe the motion of something, we describe its motion relative to something else Reference point- position in which motion is compared

4. Speed Measure of how fast something is moving Speed=Distance/Time Key words: Rate= __________ Per= __________

5. UNITS! When describing numbers we must always include units Any combination of distance units over time units is used for speed.

6. DistanceTime Speed Units

7. Instantaneous Speed- speed at a particular moment; can be changing Average Speed- speed over the course of a trip – Average Speed= Total Distance/Time Interval What does the speedometer show? __________

8. Speed Example Problem If a car travels 400m in 20 seconds how fast is it going?

9. Time Example Problem In a competition, an athlete threw a flying disk 139 meters through the air. While in flight, the disk traveled at an average speed of 13.0 m/s. How long did the disk remain in the air?

10. Distance Example Problem How far can you get away from your little brother with the squirt gun filled with paint if you can travel at 3 m/s and you have 15s before he sees you?

11. Velocity Speed in a given direction – Example: 60 m/s north

12. SpeedVelocity

13. Both cars are moving at 60 km/h Does this car have constant speed? Does this car have constant velocity? Does this car have constant speed? Does this car have constant velocity

14. Graphing Slope= Rise/Run What is the slope from 0-1 on the x-axis? What is the slope from 2-3 on the x-axis? What is the slope from 0-6 on the x-axis?

15. Distance-Time Graphs

16. Acceleration Rate at which velocity changes – Acceleration= change in velocity/time interval – Change in velocity= Final Velocity- Initial Velocity – Time interval= Final time- Initial time In science refers to an increase in speed, a decrease in speed, or a change in direction Can be confusing because it is a rate of a rate

17. Acceleration Rate at which velocity changes Acceleration= Change of Velocity/ Time Interval In science the word acceleration can me speeding up, slowing down, or changing directions – Acceleration can be confusing because it is a rate of a rate SpeedTime Acceleration

18. Acceleration Problem Toon Train is traveling at the speed of 10 m/s at the top of a hill. Five seconds later it reaches the bottom of the hill and is moving at 30 m/s. What is the rate of acceleration of Toon Train?

19. Free Fall 9.8 m/s 2 = acceleration due to gravity a=∆v/∆t-We can insert g for a when objects are in free fall g=∆v/∆t-Which equation should we use to determine velocity? ∆v=gt-Which equation should we use to determine time? t=∆v/g

20. What if you throw an object upward… What is its change in velocity? ____________

21. Dollar Bill Activity Page 21