Do Now
• A student enters the building and
walks 40m due west and then
turns on the hallway and walks
60m due north. What is the
student’s displacement?
• Please make sure you draw a
picture !
Homework
• Castle Learning – Velocity and
Speed
Negative 10 Miles per
Hour?
Velocity and Speed
Velocity vs. Speed
• VELOCITY
– change in DISPLACEMENT occurring over time
– Includes both MAGNITUDE and DIRECTION
• VECTOR
• SPEED
– change in DISTANCE occurring over time
– Inclues ONLY MAGNITUDE
• SCALAR
Average Velocity
v
=
d
t
=
Δd
Δt
What does this remind you of?
SLOPE OF AWhat
GRAPH!
is happening in this
Position vs. Time
Position
Position
graph?
INCREASING
SLOPE
CONSTANT
CONSTANT
POSITIVE
ZERO
SLOPESLOPE
Time
Moving with
Motionless
INCREASING
CONSTANT
Object
positive
velocity
velocity
Example
• Tom gets on his bike at 12:00 in the
afternoon and begins riding west. At
1:00 he has ridden 15 miles.
– What was his average velocity during his
ride?
vavg = d / t
vavg = 15 mi / 1 hr
vavg = 15 mi / hr WEST
Average Speed
Total Distance
vavg =
Total Time
OR
vavg
v1  v2
=
2
Does NOT include DIRECTION!
Example
• Sally gets up one morning and decides to
take a three mile walk. She completes the
first mile in 8.3 minutes, the second mile
in 8.9 minutes, and the third mile in 9.2
minutes.
– What is her average speed during her walk?
vavg = d / t
vavg = 3 mi / (8.3 min + 8.9 min + 9.2 min)
vavg = 0.11 mi / min
Using v-t Graphs
Velocity (m/s)
Velocity vs. Time
35
30
25
20
15
10
5
0
-5 0
-10
-15
-20
What can we DO
with a v-t graph?
1
2
3
4
5
6
7
8
9
10
11
Find distance
traveled
Time (s)
Area
under
under
the
graph to find
How doArea
you use
thethe
v-tgraph
graph
DISTANCE
AVERAGE
DISPLACEMENT?
TRAVELED?
VELOCITY?
Area
AreaononTOP
TOPand
= POSITIVE
BOTTOM
Area
both
onconsidered
BOTTOMPOSITIVE
= NEGATIVE
Find
displacement
Essential Questions
• What is the difference between velocity and
speed?
• Which is more relevant to daily life?
• What do we need to measure to measure
someone’s speed?
• Practice and Worksheet problems.