1. Describing Motion

2. Speed The distance an object travels in a certain amount of time.
Average speed – Total distance divided by total time
Constant speed - Speed that does not change over time
On your paper, describe an example of an object at a constant speed.

3. What is the formula for calculating speed?
Speed equals distance divided by time. S = d t

4. Let’s Practice Calculating Speed
In your notebook, calculate this problem. Make sure you show all work!
One side of a track is about 100 meters long. If it takes a person 20 seconds to run its length, how fast was the person running?

5. Remember to label the UNITS!!
Check Your Work
One side of a track is about 100 meters long. If it takes a person 20 seconds to run its length, how fast was the person running?
Speed = Distance ÷ Time
Speed = 100 m ÷ 20 s
Speed = 5m/s
Remember to label the UNITS!!

6. Velocity An object’s speed and direction at a given time
The wind is blowing 65 km/hr from the North.
On your paper, describe an example of velocity.

7. Acceleration
A change in the direction or velocity of an object over time – which may be:
A change in speed
Starting
Stopping
Speeding up (positive acceleration)
Slowing down (negative acceleration)
A change in direction
Acceleration is caused by unbalanced forces.
On your paper, describe an example of an object accelerating.