1. Velocity & Distance vs Time Graphs
Chapter 2.1

2. In Physics, speed and velocity do not mean the same thing.
Speed= how fast something is moving
Velocity= how fast and in what direction
Velocity= distance/time

3. Practice Problem:
The speedometer of a car moving northward reads 60 km/h. It passes another car that travels southward at 60 km/h.
Do both cars have the same speed?
Yes
Do both cars have the same velocity?
No, the cars have opposite velocities because they are moving in opposite directions

4. Constant Velocity
Occurs when an object has constant speed and constant direction

5. Practice Problem
A racecar is traveling around a circular track at a constant speed of 200 km/h. Does the car travel at constant velocity?
No, even though the driver is always traveling the same amount to the left, the motion is always changing direction
Constant velocity requires constant speed in a straight line

6. Changing Velocity
If the speed or the direction (or both) of an object are changing, the velocity is changing

7. Practice Problem:
What three controls are used in a car to change the cars velocity?
Gas pedal (increase speed)
Brake pedal (decrease speed)
Steering wheel (change direction)

8. Distance vs. Time Graphs
X axis: always time
Y axis: always distance
Slope of line = distance/time
Slope tells you what happens to speed of the object

9. What is happening in this graph?
Distance is not changing
Time is increasing
Object is not moving
Speed is 0 m/s

10. What is happening in this graph?
Distance is increasing as time increases
Straight line tells you object is moving at constant speed

11. What is happening in this graph?
Two objects started as same spot and traveled same distance but in different times
Dashed line has steeper slope so it traveled faster
Both traveled at different constant speeds

12. What is happening in this graph?
Distance and time both increasing but not at same rate throughout
Speed is increasing as time goes on
Object is accelerating

13. What is happening in this graph?
Object is moving
Object is slowing down

14. What is happening in this graph?

15. Which graph shows one person started 10 yards further ahead of the other person?

16. Which graph shows both people running at the same speed?