1. Physical Science Section 2.1
Describing Motion
Physical Science Section 2.1

2. Motion
You can tell something moved if it has changed position relative to a stationary object
Reference Point- stationary object- helps you know how far something moved
Relative motion- motion may not be obvious
Sitting in your chair, you are not moving relative to the room
You are moving relative to other planets

3. Motion Distance- how far on object moves
Measured in meters
Displacement- distance and direction of object’s change in position from the starting point

4. Motion Speed- Distance an object travels per unit time
Speed = distance/ time
Units of speed: m/s
Units of distance: m
Units of distance s
Constant speed- when an object neighter speeds up nor slows down
Cruise control

5. Motion Most of the time speed changes over time
Average Speed- a good way to describe speed of motion when speed in changing
Total distance traveled divided by total time of travel

6. Motion Instantaneous speed- speed at a specific point in time
Speedometer
Distance-time graph- slope represents speed
Plotting a distance-time graph
Distance on vertical
Time on horizontal
Make sure scales make sense with your data
Plot data points
Draw line connecting points

7. Motion Velocity- speed and direction
Must include N, E, W, S or left, right, up, down
Velocity changes continually around a race track