1. Chapter 2: Motion Along a Line
Position & Displacement
Speed & Velocity
Acceleration
Describing motion in 1D
Free Fall
CQ: 1, 2, 3, 4.
P:1, 11, 13, 25, 27, 29, 47, 50.

2. Applications Destination times
Design packing materials & road barriers
Airbag deployment speed
Simulations (movies & games)

3. Speed Speed = rate of travel at a given moment of time
Distance traveled = total length of the curved path

4. Initial/Final Notation
Same rules apply for all variables

5. Delta Notation
called Displacement

6. Velocity (m/s)
When Dt is small, Dx/Dt is the instantaneous velocity v.

7. Graphs
Wilson (12) x vs t
Giambattist (21) +, -, 0 accel.

8. Acceleration (m/s/s)
If Dt is small, Dv/Dt is called the instantaneous acceleration and labeled “a”.

9. Ex. Car Acceleration from 10m/s to 15m/s in a time of 2.0 seconds.
from 10m/s to 15m/s in a time of 2.0 seconds.
In this class we only use average acceleration and often drop the “avg” notation from acceleration.

10. Velocity Formula

11. acceleration
Wilson (15) negative acceleration

12. Average Velocity with Uniform Acceleration
Uniform Acceleration = constant valued acceleration
During uniform acceleration, average velocity is halfway between vo and v:

13. Average Velocity Formula

14. Displacement Formula

15. V-squared Equation

16. Kinematic Equations with Constant Acceleration

17. Ex. Human Acceleration
In the 1988 Olympics, Carl Lewis reached the 20m mark in 2.96s (Bolt: 2.87s)

18. Ex: V2 Equation Approximate Stopping Accelerations in m/s/s:
Approximate Stopping Accelerations in m/s/s:
Dry Road: ~ 9 (anti-lock) ~ 7 (skidding)
Wet Road: ~ 4 (anti-lock) ~ 2 (skidding)
At 60mph = 27m/s, what is the skid-to-stop distance on a wet road?

19. Scalars & Vectors Scalar: size only e.g. speed, distance, time
Vector: magnitude and direction
e.g. displacement, velocity, acceleration
In one-dimension the direction is determined by the + or – sign.
In two-dimensions, two numbers are required.

20. Motion Diagrams Are velocity-position diagrams
Are velocity-position diagrams
More visual than a graph of x or v vs. time
Arrow gives direction, length represents the speed (use a dot for zero speed)
(net) force required to change velocity
Example: car speeding up to left

21. Free-Fall Acceleration
a = 9.8m/s/s in downward direction
Ex. Speed of object dropped from rest after 1.0, 2.0, 3.0 seconds:
v = vo at
v(1.0s) = 0 + (-9.8)(1.0) = -9.8m/s
v(2.0s) = 0 + (-9.8)(2.0) = -19.6m/s
v(3.0s) = 0 + (-9.8)(3.0) = -29.4m/s /

22. Activities
Moving Man phet animae
Textbook type problems

23. Summary: speed: rate of travel average speed: distance traveled/time.
displacement: change in position
velocity: rate position changes
acceleration: rate velocity changes
kinematic equation set
free fall: constant acceleration.
graphs and slopes