1. Describing Motion
Chapter 9.1
Page 338

2. Objectives for 9.1 Know how to determine if an object is in motion.
Know what a reference point is.
Explain how objects can have different speeds depending on the reference point.

3. What is Motion?
An object is in motion when its distance from another object is changing.

4. Reference Points
To determine if something is in motion, you need a reference point.
Reference Point: a place or object used for comparison to determine if something is in motion.

5. Relative Motion
Relative motion is the speed you are traveling in comparison to a specific reference point.
Are you moving?
With reference to your chair: 0 mph
With reference to the moon: 820 mph
With reference to the sun: 67,000 mph

6. Describing Distance
Distance is the length of a path between two points
The SI unit of length to be used depends on the size of the object being measured.
Long Distances are measured in Kilometers (km)
Large objects are measured in meters (m)
Small objects are measured in centimeters (cm)
Very small objects are measured in millimeters (mm)

7. Distance and Displacement
Distance is the total length of the actual path between two points.
Displacement is the length and direction of a straight line between starting and ending points.

8. Vectors
A vector is a visible way (an arrow) to show the magnitude (amount) and direction of a quantity.
Same direction,
Different magnitude
Same magnitude,
Different direction