The document discusses key concepts in physics related to motion, speed, velocity, and acceleration, explaining their definitions and differences. It emphasizes the importance of vectors and scalars, the calculation of average speed and velocity, and the significance of direction in measuring velocity. Additionally, it outlines how acceleration is determined by changes in velocity over time and discusses examples of each concept.

1. Motion, Speed, Velocity
Motion, Speed, Velocity
and Acceleration
and Acceleration

2. VECTORS AND SCALORS
VECTORS AND SCALORS
ORIGIN - POINT AT WHICH BOTH VARIABLES
ORIGIN - POINT AT WHICH BOTH VARIABLES
ARE AT 0 (ZERO)
ARE AT 0 (ZERO)
MAGNITUDE – SIZE
MAGNITUDE – SIZE
VECTORS – DIRECTION (represented by
VECTORS – DIRECTION (represented by
arrows)
arrows)
SCALARS – QUANTITIES W/OUT DIRECTION
SCALARS – QUANTITIES W/OUT DIRECTION
(ex distance m, time s, temp C)
(ex distance m, time s, temp C)

3. RESULTANT – SUM OF VECTORS
RESULTANT – SUM OF VECTORS
6m east plus 2 m east = 8m east
6m east plus 2 m east = 8m east
►Resulatant subtracting vectors
Resulatant subtracting vectors
►A - B = A+(-B)
A - B = A+(-B)
 A = 20 m west
A = 20 m west
 B = 5 m east
B = 5 m east
 15m
15m

4. Time Interval/Displacement
Time Interval/Displacement
►Time interval - change in time =final time
Time interval - change in time =final time
–initial time ….
–initial time ….
►formula
formula
►Displacement - Change in distance = final
Displacement - Change in distance = final
distance – initial distance
distance – initial distance
►formula
formula

5. Motion
Motion
►Motion
Motion – an object’s change in position
– an object’s change in position
relative to a reference point
relative to a reference point

6. Reference Point
Reference Point
►The Earth’s surface is used as a common
The Earth’s surface is used as a common
reference point
reference point
►A moving object can be used as a
A moving object can be used as a
reference point as well
reference point as well

7. Speed
Speed
►Speed
Speed is the distance traveled divided by
is the distance traveled divided by
the time interval during which the motion
the time interval during which the motion
occurred
occurred
►Normally, objects do not travel at a
Normally, objects do not travel at a
constant speed
constant speed
►Average Speed -
Average Speed - total distance
total distance
total time
total time

8. Which Distance?
Which Distance?
► Farmer Jones drives 6 miles down a straight
Farmer Jones drives 6 miles down a straight
road. he turns around and drives 4 miles back.
road. he turns around and drives 4 miles back.
What was his average speed for this trip if it
What was his average speed for this trip if it
took 1 hour?
took 1 hour?

9. Your answer to this problem
Your answer to this problem
depends on your interpretation of
depends on your interpretation of
"distance traveled". You could say:
"distance traveled". You could say:
► The
The total distance
total distance traveled by Farmer Jones is 10
traveled by Farmer Jones is 10
miles. Therefore his average speed is 10 mi/hr.
miles. Therefore his average speed is 10 mi/hr.
► The
The net distance
net distance traveled by Farmer Jones is 2 miles.
traveled by Farmer Jones is 2 miles.
Therefore, his average speed is 2 mi/hr.
Therefore, his average speed is 2 mi/hr.
► There are good reasons to use either interpretation -
There are good reasons to use either interpretation -
it's mostly a matter of preference. We will interpret
it's mostly a matter of preference. We will interpret
"distance traveled" to be
"distance traveled" to be net distance
net distance (
(also called
also called
displacement).
displacement). Farmer Jones' average speed was 2
Farmer Jones' average speed was 2
mi/hr.
mi/hr.

10. Velocity
Velocity
►Velocity
Velocity is the speed of an object in a
is the speed of an object in a
particular direction
particular direction
►Imagine two birds leave the same tree at
Imagine two birds leave the same tree at
the same time. The both fly at 10km/hr
the same time. The both fly at 10km/hr
for 5 minutes. Why don’t they end up at
for 5 minutes. Why don’t they end up at
the same place?
the same place?

12. Velocity
Velocity
►Velocity
Velocity appears to be very similar to
appears to be very similar to
speed, however, when describing the
speed, however, when describing the
velocity of an object you need to provide
velocity of an object you need to provide
a magnitude and a direction
a magnitude and a direction
►Magnitude
Magnitude – the speed of the object
– the speed of the object
►Direction
Direction – the direction the object is
– the direction the object is
moving
moving
►Pg 43 demo
Pg 43 demo

13. Velocity
Velocity
►Ex) A bus has a velocity of 35miles/hr
Ex) A bus has a velocity of 35miles/hr
heading west
heading west

14. Resultant Velocity
Resultant Velocity
►An object can have a resultant velocity if it
An object can have a resultant velocity if it
is experiencing more than one motion.
is experiencing more than one motion.
►For example if a person walks down the
For example if a person walks down the
center of a bus while it is in motion there
center of a bus while it is in motion there
are two velocities occurring.
are two velocities occurring.
 1. The movement of the bus
1. The movement of the bus
 2. The movement of the person inside the
2. The movement of the person inside the
bus
bus

15. Example
Example
15 m/s + 1 m/s = 14 m/s

16. Example
Example
15 m/s + =
1 m/s 16 m/s

17. Acceleration
Acceleration
►Acceleration
Acceleration is the rate at which velocity
is the rate at which velocity
changes over time
changes over time
 An object accelerates if its speed, direction, or
An object accelerates if its speed, direction, or
both change
both change
►Average acceleration =
final velocity – starting velocity
time it takes to change velocity

18. Acceleration
Acceleration
►Example
Example
 A car on the highway is traveling 55 mi/hr
A car on the highway is traveling 55 mi/hr
and it passes another car. In order to pass,
and it passes another car. In order to pass,
the car has to accelerate to 65 mi/hr. The car
the car has to accelerate to 65 mi/hr. The car
reaches this velocity 40 seconds later. What
reaches this velocity 40 seconds later. What
is the average acceleration of the car?
is the average acceleration of the car?

19. Acceleration and Velocity
Acceleration and Velocity
►As velocity
As velocity increases
increases, so does
, so does
acceleration
acceleration
►As velocity
As velocity decreases
decreases, so does
, so does
acceleration
acceleration
►When direction changes, so does
When direction changes, so does
acceleration
acceleration
►When there is a
When there is a constant velocity
constant velocity, there
, there
is no acceleration
is no acceleration