1. Physical Science Chapter 11 Displacement and Coordinate Systems

2. Journal Entry Six Invent two scenarios in which the displacement would be less than the distance. Scenario One: Displacement must be zero. Scenario Two: Displacement not zero.

3. Relative Motion and Frame of Motion In our previous lesson, we learned that motion is relative. Relative Motion is relative because it depends upon where you are as to whether something or someone appears to be moving. https://youtu.be/5oSrDrDLylw We also talked about the measurement of distance. The SI unit for length or distance is a meter. We will work on metric measurement at a later time.

4. Distance and Displacement What is the difference between distance and displacement? Which one has a direction included with the magnitude (number and unit)? What do we call a quantity that has both a magnitude and a direction? Which one does not have a direction included with the magnitude? What do we call a quantity that does not have a direction?

5. Arrows Represent Vectors  Vectors are Represented by Arrows.  The direction of the arrow represents the direction of the vector.  The length of the arrow is proportional to the magnitude of the vector.  The vector that represents the sum of the other vectors is called the resultant vector.  The resultant vector is always drawn from the tail or starting point (origin) of the first vector to the head of the last vector. It is the only vector that has the heads and tails touching each other.

6. Answer the questions about the vectors in this picture. What direction are the vectors going? What is the magnitude of the two vectors? Which arrow represents the resultant vector?

7. Remember distance vs. displacement.  From the corner of 5 th and Birch St, a person goes three blocks west.  Then they go three blocks north.  Which arrow represents the displacement?  What does the letter R stand for?

8. Finding the Resultant Vector There are two ways to find the resultant vector. We could measure it if we use the same units in comparison. The second way of finding the resultant vector is to use the Pythagorean Theorem to find the hypotenuse of a triangle. When the resultant vector is drawn to vectors that are at right angles, this theory does well. The theorem is a 2 + b 2 = c 2.

9. Coordinate System with a X-Y Axis  Coordinate System that has both x and y axis and x and y coordinates provides us with an origin.  The origin is the point at which both variables have the value of zero.  A distance-time graph will give us information about an object’s position at various times.  It is also helpful in determining the displacement of an object during various time intervals.

10. Where is the origin in this graph?

11. Position (Distance) – Time Graph The table on the left has the same information has the graph on the right however the graph on the right makes it more obvious at a glance that time and position (distance) are increasing.

12. Equations for Time and Position  Time Interval represented by  t is the time elapsed during motion.  So  t is equal to the t f (final time) minus the t i (initial time).  The change in position during the time interval between t i and t f is called displacement (d).  Displacement (  d) is equal to the final position or distance d f minus the initial position or distance d i.