1. Describing Motion

2. How to Describe Motion Words - the car is traveling 30 m/s due east
Equations and values - d/t = speed
100m/20s = 5m/s
Graphically -

3. With pictures

4. Vectors and Scalars
A vector is a number with units and includes direction.
Velocity is a vector - 130mph West
A scalar quantity is a number with units but does not specify the direction
Speed is a scalar quantity - 130mph

5. Vocabulary Reference point - a zero point
Position - separation of object and reference point
Distance - separation of two objects or locations, needs no reference point.
Displacement - distance and direction between two positions

6. Calculating Motion Ave. Speed = total distance s=d/t total time
Ave. Velocity = total displacement v = d/t
Or velocity 1 + velocity 2
2 only if traveling at each velocity for the same amount of time
This does not give you instantaneous speed or velocity.

7. Units for speed are m/s or cm/s or km/h
When calculating average speed or average velocity, can the instantaneous speeds change along the way?
Units for speed are m/s or cm/s or km/h
If velocity is known, you can calculate distance.
Δd = vt or df = di + vt

8. 3 Step Method Write out the equation s = d/t
Substitute in your values with units
s = 30m/10s
3) Write out answer with units.
s = 3m/s

9. A car travels 450m in 9.0 seconds find the average speed of the car.
A train is traveling 45km/hr east for 2.5 hrs. Find the displacement of the train.
A person on a bike is traveling m/s for 10s and then speeds up to 50m/s for 10s. Find the ave. speed of the bike.
A person on a bike is traveling m/s for 100m and then speeds up to 50m/s for 100m. Find the ave. speed of the bike.