Chapter 2 discusses motion in one dimension, covering essential concepts like displacement, velocity, and acceleration. Displacement is defined as a directional change in position, while average velocity is displacement over time, with both being distinct from speed. Additionally, free fall, characterized by a constant acceleration of 9.81 m/s² due to gravity, is introduced, along with relevant kinematic formulas.

1. Chapter 2
Motion in One
Dimension
Section 1
Displacement and Velocity

2. Motion
 Motion happens all around us in different directions and
different speeds.
 One – dimensional motion is the simplest form of motion.
 Example : Commuter train can move only forward and
backward along the straight track.

3. Frame of Reference
 Motion takes place over time and depends on
frame of reference.
 Frame of Reference – what you use to
measure changes in position.

4. Displacement
 Displacement is a
change in position. (Final
– Initial)
 Displacement is NOT the
same as distance
traveled.
 Displacement has a
direction.
 Right and Up is (+)
 Left and Down is (-)
Displacement

5. Displacement

6. Velocity
 Average Velocity is
displacement of an object
(Δx) divided by time
interval (Δt).
 Average Velocity can be
positive or negative
depending on the sign of
the displacement.
 If displacement is
negative, avg. velocity is
negative.
 Time interval is ALWAYS
positive

7. Guided Practice
 Open Books to pg. 44

8.  Velocity is not the same
as speed.
 Velocity describes motion
with direction and
magnitude (numerical
value);
 Speed ONLY has
magnitude.
 Ex: 55 m/s and 55 m/s
North
Velocity Vs. Speed

9. Velocity can be interpreted
graphically…

10. The motion of an object moving with constant
velocity will provide a straight-line graph of
position versus time. The slope of this graph
indicates the average velocity.

11. Section 2 Acceleration
Chapter 2
One
Dimensional
Motion

12. 2-2 Acceleration
 Acceleration measures the
rate of change in velocity.
 Has Magnitude & Direction.
 SI Units : m/s2
 Three ways to Accelerate:
 Object Speeding Up
 Object Slowing Down
 Object Changing Direction

13. Let’s Practice with Average
Acceleration...
 Sample Problem 2B
 Pg. 49 in your books.

14. Acceleration
 The slope and shape
of a graph plotting
velocity vs. time
describes the
object’s acceleration.
 When velocity on
graph is
increasing :
acceleration is positive
decreasing :
acceleration is
negative
constant : there is no
acceleration

15. Velocity Vs. Time Graphs

16. Kinematic Formulas

17. Formulas in Textbook
on Pg. 58

18. Section 3
Falling Objects
Chapter 2
One Dimensional
Motion

19. Free Fall
 Free fall is acceleration due to gravity.
 Free fall acceleration is constant.
 Magnitude of free fall is 9.81 m/s2
 Direction of free fall is directed downward.
 negative direction (-)
 Free fall is denoted with the symbol g. (Sometimes may
be ‘a’ for acceleration due to gravity)

20. Free Fall
 In a vacuum, in the absence of air resistance, all objects
fall at the same rate.

21. What goes up must come down.
What causes an
object that has been
thrown up into the air
to come back down?
Free-Fall Acceleration
due to gravity is
always directed
downward and pulling
an object towards
Earth’s surface.

22. Recall Information
 Remember we learned about a formula that can be
used to find final velocity at ANY displacement…
vf
2 = vi
2 + 2aΔx (time is not needed)
 We use this same formula but we change x to y
vf
2 = vi
2 + 2aΔy

23. Guided Practice
 Open books to pg. 63 Sample Problem 2F