1. Speed measures how fast position changes
Section 1.2 Outline
Speed measures how fast position changes

2. Position can change at different rates
speed: a measure of how fast something moves
rate at which distance changes compared to time
a measurement; can be fast or slow
speed and position are related by time – speed measures how quickly position change

3. A. Calculating Speed
objects that travel at different speeds move different distances in the same amount of time
2) S = d/t (S = speed, d = distance, t = time)

4. B. Average Speed speed is not constant; it is always changing
moment-to-moment speed (instantaneous) is difficult to measure
easiest to calculate average speed over a distance

5. C. Distance-Time Graphs
shows how speed relates to distance and time
shows how both distance and speed change with time
a flat, or horizontal, line shows a speed of 0 m/s
time is on horizontal, or x-axis and distance is on vertical, or y-axis

6. II. Velocity includes speed and direction
1) velocity: a speed in a specific direction
2) example: 3 m/s south

7. A. Velocity 1) to calculate, need both speed and direction
2) vector: a quantity that has both size and direction
3) represented by an arrow (size and direction)

8. B. Velocity versus speed
two objects may have same speed, but different velocities
average speed depends on total distance traveled
average velocity depends on total distance from starting point