2. Motion – Part 1 Frame of Reference Distance vs. Displacement Average Speed

3. Look at the figures. In fig.1, the car is to the right of the tree. In fig.2, after 2 seconds, the car is to the left of the tree. As the tree does not move, the car must have moved from one place to another. Therefore, here the tree is considered as the frame of reference.

4. Frame of Reference clip

5. Distance vs. Displacement Distance- total path length, no particular direction Displacement- The length of the straight line drawn from the initial position to the final position of an object. – The change in position of an object – Has a specific direction

6. Distance vs. Displacement You drive the path, and your odometer goes up by 8 miles (your distance). Your displacement is the shorter directed distance from start to stop (yellow arrow). What if you drove in a circle? start stop

7. Distance Vs. Displacement cont. Distance and displacement are not necessarily equal to one another. Calculating displacement – Assign + and – designations for the direction + to the right, N, or E - to the left, S, or W – Displacement ∆x= change in position Final position- initial position ∆x= X f -X i

8. Displacement practice Start= 5m End= 10 m X i = -1 m X f = 5m X i = 5m X f = -1m

9. What is speed?

10. Average speed Average speed = Total distance Total Time

11. Average Speed practice problem What is the average speed of a car that travels 600 Km in 10 hours? x= t= v= Convert your answer to m/s.

12. Average Speed Practice problem If a frisbee was thrown horizontally 138.56m with a speed of 13m/s, how long did the frisbee remain aloft? x= t= v=