This chapter introduces concepts of kinematics including displacement, distance, speed, velocity, average velocity, instantaneous velocity, acceleration, and uniformly accelerated motion. Key equations relating position, velocity, and acceleration in one dimension are derived. Examples are provided to demonstrate applying these equations to problems involving uniform and accelerated linear motion as well as free fall. A lab experiment is described to measure the acceleration due to gravity using a Behr free fall apparatus.

1. Essential College
Physics
Chapter 2

2. Chapter 2 Objectives
• Distinguish between
displacement and distance.
• Distinguish between speed and
velocity.
• Understand average and
instantaneous velocity.

3. Chapter 2 Objectives
• Understand acceleration and its
relation to velocity and position
in one-dimensional motion.
• Solve problems involving
uniform acceleration in one
dimension.

4. Kinematics:
The branch of physics
that deals with pure
motion without
reference to the masses
or forces involved.

5. Frames of Reference (19)

6. Frames of Reference (19)

7. Displacement
0x x x  
Displacement, m
Final Position, m
Initial Position, m

8. Displacement vs. Distance (20)
• Figure 2.4
• Conceptual Example 2.1

9. Average Velocity (21)
x
x
v
t



Average Velocity, m/s
Displacement, m
Time Interval, s

10. Uniform Linear Motion
x v t  
Displacement, m
Velocity, m/s
Time, s

11. Uniform Linear Motion Lab
• Lab Report Format
• Probe ware and light gates
• Purpose: Determine if the motion on the
dynamics track is uniform linear motion.

12. Average Velocity (21)
• Figure 2.6

13. Average Velocity (21)
• Figure 2.6 c

14. Average Velocity (21)
• Figure 2.6 d

15. Average Speed (22)
distance
v
t



16. Average Velocity / Average Speed
Example 2.2 (22)

17. Instantaneous Velocity (23)
• What the speedometer reads
• A calculus concept

18. Average Acceleration (26)
x
x
v
a
t



Average Acceleration, m/s2
Change in
Velocity, m/s
Time Interval, s

19. Average Acceleration (27)
• Reviewing New Concepts
• Example 2.5

20. Graphical Interpretation of Motion
Position-Time Graph
• The slope is the speed
• My example
Velocity-Time Graph
• The slope is the average
acceleration
• The area under the
curve is the
displacement
• My example

21. Kinematics Equations
• Apply to uniformly accelerated motion.
• Derived from the definitions of average
velocity and average acceleration.

22. Definition of Acceleration



0v v
a
t 0
 0v v at
becomes

23. Two Definitions of Average Velocity

 

0
0
x x x
v
t t t
if 0x 0 0t 0
 1
02
v (v v )

24. Set the two v ‘s equal
 1
02
x
(v v )
t
Substitute  0v v at
And rearrange

25. Kinematics Equations
aka The Free Fall Formula
  21
0 2
x v t at

26. Remember
 1
02
x
(v v )
t
It easily becomes
 1
02
x (v v )t

27. The Definition of Acceleration

 0v v
a
t
becomes

 0v v
t
a

28. Substitute into
 1
02
x (v v )t
and rearrange to obtain
 2 2
0v v 2ax

29. Kinematics Equations
 0v v at
 1
02
x (v v )t
  21
0 2
x v t at
 2 2
0v v 2ax

30. Uniformly Accelerated Motion
• Example 2.6 (29)
• Example 2.7 (30)
• Example 2.8 (31)
• Example 2.9 (31)
• Example 2.10 (32)

31. Free Fall
• Vertical uniformly accelerated
motion
• g=9.80 m/s2
• Formulas are the same, but replace x
with y and a with g or –g.

32. Free Fall Examples
• Example 2.11 (34)
• Example 2.12 (34)

33. Behr Free Fall Lab
• The purpose is to confirm the accepted value
for the acceleration due to gravity
• The Behr free fall apparatus
• Using the Vernier caliper
http://www.youtube.com/watch?v=ZUNoW
Ww6V10
• Using Microsoft Excel

34. Behr Free Fall Lab
• Explanation of calculations and sample
• Calculation of slope of the velocity-time
graph should yield your value for g
• Calculate percent error
Accepted Experimental
%Error 100%
Accepted

 

35. Chapter 2 Problem Sets
• Honors: P. 38, Ex. 32, 34, 40, 46,
48, 62, 66, 68, 74, 82, 100
• UConn: P. 38, Ex. 34, 38, 40, 46,
48, 62, 66, 70, 74, 80, 82, 84, 96