10/28 (p 42 ) Motion Notes- Speed
An object is in motion if it changes
position relative to a reference point.
• Objects that we call stationary—such as a
tree, a sign, or a building—make good
reference points.
The passenger can use a tree as a reference point to decide if the
train is moving. A tree makes a good reference point because it is
stationary from the passenger’s point of view.
Reference Point: A place or object used
to compare and determine if an object is
in motion. Should not be moving, should
be visible to compare.
http://rpdp.net/terms/mid/full/m/motion.htm
Describing Motion
Whether or not
an object is in
motion depends
on the reference
point you choose.
• Earth rotates
on its axis
at 1,100 mph or
1670 km/hr.
• Earth orbits
the Sun at
68,000 mph or
107,000 km/hr
• The whole galaxy rotates
at 490,000 mph
Distance
When an object moves, it goes from point
A to point B – that is the DISTANCE it
traveled. (SI unit is the meter)
Distance is how far an object has moved
during its motion.
B
A
Measuring Distance
• Meter – international unit for measuring
distance.
1 mm
= 50 m
Displacement
Displacement is how
far out of place the
object is; it is the
object’s overall change
in position, directly
from the starting to
the ending point. In this
example, the
displacement is 5 km
northeast whereas the
distance is 1+1+2+3=
7km
Formula: Speed = Distance(m)
Time(s)
Calculating Speed
• Speed (S) = distance traveled (d) / the
amount of time it took (t).
• Copy on left page:
D
S
T
S (speed, how fast, rate)= d/t SI unit m/s
D (distance, how far)= s x t SI unit m
T (time, how long) = d/s SI unit s
Calculating speed
S = d/t
• If I travel 100 kilometer in one hour then I
have a speed of…
• 100 km/h
• If I travel 1 meter in 1 second then I have a
speed of….
• 1 m/s
• If I travel 100 km in 2 hours, I have a
speed of 100 km/2 h= ____
A snail crawls 1 m in 100 seconds.
What is the speed of the snail?
Speed
=
=
distance
time
1m
=
.01 m/s
100s
Problem 1 (left hand side p.): Create a problem
like the one above and solve to find the speed.
Please use different numbers!
Problem 2 =I ran for 2 hours at a speed of 6
km/h. How far did I run?
Far means distance, time or speed?
Types of Speed
• Constant speed = unchanging speed over
a certain period of time.
• Speed is usually NOT CONSTANT
– Ex. Cars stop and go regularly
– Runners go slower uphill than downhill
• Average speed = total distance
traveled/total time.
• Instantaneous speed= speed at any given
time.
Instantaneous Speed
What is
instantaneous
speed?
Instantaneous
speed is the
speed of an
object at a
certain time.
Speed = Distance/time
Average speed = Total distance/Total time
Problem 3: Tina ran 1000 m in 3 minutes.
Then ran another 1000 m uphill in 7
minutes.
a. Did she have a constant speed?
b. Find her average speed.
• A) 100 m/min
• B) 2000 m/min
• C) 10 m/min
• D) 200 m/min
• E) 20 m/min
Total Dist. = 1000 m + 1000 m = 2000 m
Total Time = 3 min + 7 min = 10 min
Ave speed = total dist/total time =
2000m/10 min = 200 m/min
Problem 4
Jane ran 10 km in 2 hours, and the next 5
km in 1 hour.
Did she have a constant speed? (Find
speed for each part of her run, is it the
same?).
What is her average speed? (Total d/total t)
What would be the best reference point to tell if
the canoe is moving or not?
a. The water
b. The sky
c. The shore
d. The lighthouse
e. The island
An object is in motion if it changes
position relative to a __________ point.
• Objects that we call stationary—such as a
_____, a sign, or a building—make good
reference points.
The passenger can use a tree as a reference point to decide if the
train is moving. A tree makes a good reference point because it is
stationary from the passenger’s point of view.
Reference Point: A _________ or
__________used to compare and determine if
an object is in motion. Should _______be
___________, should be ________ to compare.
Distance
When an object _______, it goes from
point A to point B – that is the
DISTANCE it traveled. (SI unit is the
_________ )
Distance is how _____ an object has
moved during its motion.
B
A
Displacement
Displacement is how
far out of place the
object is; it is the
object’s ______ change
in position, directly
from the _______ to
the ending point. In this
example, the
displacement is 5 km
northeast, whereas the
distance is 1+1+2+3=
7km
______: Speed = Distance(m)
Time(s)
Calculating Speed
• Speed (S) = distance traveled (d) / the
amount of time it took (t).
D
S
T
S (speed, how fast, rate)= d/t SI unit m/s
D (distance, how far)= s x t SI unit m
T (time, how long) = d/s SI unit s
Calculating speed
S = d/t
• If I travel 100 kilometer in one hour then I
have a speed of…
• 100 km/h
• If I travel 1 meter in 1 second then I have a
speed of….
• 1 m/s
• If I travel 100 km in 2 hours, I have a
speed of 100 km/2 h= ____
A snail crawls 1 m in 100 seconds.
What is the speed of the snail?
Speed
=
=
distance
time
1m
=
.01 m/s
100s
Problem 1 (left hand side p.): Create a problem
like the one above and solve to find the speed.
Please use different numbers!
Solve on left hand side page:
Problem 2 =I ran for 2 hours at a speed of 6
km/h. How far did I run?
Far means…. distance, time or speed?
Types of Speed
• Constant speed = ________ speed over a
certain period of time.
• Speed is usually ______ CONSTANT
– Ex. Cars stop and go regularly
– Runners go slower uphill than downhill
• Average speed = _______ distance
traveled/total ________.
• Instantaneous speed= speed at ______
given ________.
Instantaneous Speed
Instantaneous
speed is the
speed of an
object at a
certain time.
Speed = Distance/time
Average speed = Total distance/Total time
Problem 3: Tina ran 1000 m in 3 minutes.
Then ran another 1000 m uphill in 7
minutes.
a. Did she have a constant speed?
b. Find her average speed.
A) 100 m/min
B) 2000 m/min
C) 10 m/min
D) 200 m/min
Problem 4 Solve on left hand
side page:
Jane ran 10 km in 2 hours, and the next 5
km in 1 hour.
Did she have a constant speed? (Find
speed for each part of her run, is it the
same?).
What is her average speed? (Total d/total t)
OQ: How long would it take a car driving at
100 km/h to go 600 km?
11/6
Motion Notes: Velocity
IQ:
Did the football in the cartoon move? Did the
kid move? How can you tell?
It has both speed and
direction. Ex. 50km/h south,
10m/s NE
Do all these planes have
the same speed?
Is
their
velocity
different?
Describing Motion
Velocity
Because velocity depends on direction as well
as speed, the velocity of an object can change
even if the speed of the object remains
constant.
The speed of this car
might be constant, but
its velocity is not
constant because the
direction of motion is
always changing.
Velocity
Velocity is a description of an object’s
speed and direction.
As the sailboat’s direction
changes, its velocity also changes,
even if its speed stays the same.
If the sailboat slows down at the
same time that it changes
direction, how will its velocity be
changed?
Speed vs. Velocity Usain Bolt
It has both ______ and
___________. Ex. 50km/h
______, ________ NE
Describing Motion
Velocity
Because velocity depends on direction as well
as speed, the velocity of an object can change
even if the speed of the object remains
constant.
The speed of this car
might be constant, but
its _________ is not
constant because the
__________ of motion
is always __________.
Velocity
Velocity is a description of an object’s
speed and direction.
As the sailboat’s direction
changes, its velocity also changes,
even if its speed stays the same.
If the sailboat slows down at the
same time that it changes
direction, how will its velocity be
changed?
Problem : Rocket 1 goes 2000 km in 2 hrs.
towards the East. Rocket 2 goes 3600 km
in 3 hrs. towards the East. Do they have the
same
a. Speed?
b. Velocity? Explain.
Which of the following could be the velocity
of a moving object?
A. 12 m/s
B. 100 m NE
C. 0.5 m/s W
D. 1300 s N
11/7 Speed Challenge lab
IQ: Word bank: Constant speed, velocity,
average speed, instantaneous speed
a. I hiked up the mountain at a speed of 1 m/s_____________
b. At t=10s the rocket was going1000 m/s________________
c. The plane flew at 700 km/h E-__________
d. The earth rotates at 1100 mph.___________.
11/05 p. 46 Motion Notes: Acceleration
IQ: Describe the motion of each car:
Car (a) is going at ________________
Car (b) is ________________
Car (c) is ________________
• Speed and velocity review (HW)
• Fill in the blanks for Velocity notes.
• Answer the problem on slide 4.
• Instantaneous vs. Average speed or
velocity
Acceleration
• Acceleration is a change in
speed or direction of an object.
• Accel = final vel.-initial vel. m/s
m/s22
Time
Calculating Acceleration
• If an object is moving in a straight line
Final _ speed  Initial _ Speed
Acceleration 
Time

Units of acceleration:
 m/s2
or m/s/s
Calculating Acceleration
Final _ Speed  Initial _ Speed
Acceleration 
Time
16m / s  0m / s

4s
 4m / s 2
0s
1s
0 m/s
4 m/s
2s
8 m/s
3s
12 m/s
4s
16 m/s
A cheetah goes from 0 to 60 mi/h in 3s.
What is its acceleration?
• A baseball going at 60 km/h reaches the
catcher’s glove in 4 seconds. What is its
average acceleration?
Calculating Acceleration
As a roller-coaster car starts down a slope, its
speed is 4 m/s. But 3 seconds later, at the
bottom, its speed is 22 m/s. What is its
average acceleration?
What information have you
been given?
Initial speed = 4 m/s
Final Speed = 22 m/s
Time = 3 s
Types of acceleration
• Increasing speed, positive accel.
– Example: Car speeds up at green light
• Decreasing speed, negative
accel./deceleration
screeeeech
– Example: Car slows down and comes to a
stop at red light, an arrow or a bullet after
being shot. (Add to your notes)
• Changing Direction
– Example: Car takes turn (can be at constant
speed)
Centripetal acceleration
Is the car below accelerating?
Physics of NFL
• A car that starts from rest and speeds up to 30
km/hr in 10 seconds has positive acceleration.
Acc=
• A car that slows down, and comes to a stop from
going 100 km/hr in 5 secs. has a negative
acceleration or deceleration.
Acc=
Question
• How can a car be accelerating if its speed
is a constant 65 km/h?
• If it is changing directions it is accelerating
• Acceleration while skydiving
• Complete yellow Motion map.
• Tape on p. 46.
• What happens to the motion of a baseball
after it is hit by the batter and flies towards
the outfield? It
a. Goes at a constant speed
b. Accelerates
c. Decelerates
d. Has a speed of zero.
Acceleration
• Acceleration is a __________ in
________ or ___________ of an
object.
m/s22
• Accel = final vel.-initial vel. m/s
Time
Calculating Acceleration
• If an object is moving in a straight line
Final _ speed  Initial _ Speed
Acceleration 
Time

Units of acceleration:
 m/s2 or m/s/s
Calculating Acceleration
Final _ Speed  Initial _ Speed
Acceleration 
Time
16m / s  0m / s

4s
 4m / s 2
0s
1s
0 m/s
4 m/s
2s
8 m/s
3s
12 m/s
4s
16 m/s
Calculating Acceleration
As a roller-coaster car starts down a slope, its
speed is 4 m/s. But 3 seconds later, at the
bottom, its speed is 22 m/s. What is its average
acceleration?
What information have you been
given?
Initial speed = 4 m/s
Final Speed = 22 m/s
Time = 3 s
Acc=
Types of acceleration
• _________ speed, _________ accel.
– Example: Car speeds up at green light
• ____________ speed, negative
accel./_____________
screeeeech
– Example: Car slows down and comes to a stop
at ________ light
• Changing ____________
– Example: Car takes ______ (can be at constant
speed)
Centripetal acceleration
Is the car below accelerating?
Solve for Acceleration.
• A car that starts from rest and speeds up to 30
km/hr in 10 seconds has __________
acceleration=
• A car that slows down, and comes to a stop from
going 100 km/hr in 5 secs. has a ____________
acceleration or deceleration=
Question
• How can a car be accelerating if its speed
is a constant 65 km/h?
OQ: Which of the following is NOT
accelerating?
a. The earth
b. A skier going downhill
c. A car sitting in the driveway
d. A school bus stopping.
Centripetal Acceleration
• When you move in a circular motion, you
have continuous acceleration (always
changing direction)
• Acceleration from spinning
• Centripetal means “toward the center”
OQ: Draw the v/t graph for an object that
starts out at a high velocity, slows down
constantly and comes to a stop.