Download Motion

Date: 10/15/2007
Monday
Aim: What is the difference between speed &
velocity?
Do Now: What is motion?
Homework: Read pgs 70 – 73 in textbook &
Answer Ques. 1 & 2 on pg 72 (Practice
Problems) – Write out Formula, Plug in #’s,
Calculate & Give Units
What is motion?
• A change in position
over a certain
amount of time or,
• The movement of an
object
• The rate at which an
object moves
(how fast or slow)
What is speed?
How can speed be
calculated?
S
Speed = Distance
Time
D
T
1) Carl Lewis runs a 100 meter race in 10
seconds. What is his average speed?
Avg. Speed = Total distance/Total Time
Avg. Speed = 100 m/10 sec
Avg. Speed = 10 m/s
2) How much time does it take for a
cheetah to travel 84 meters at a speed
of 28 m/s?
Time = distance/speed
T = 84 m
28 m/s
T = 3 sec.
3) What distance does a jogger go if she
runs with a speed of 160 m/min for 20
minutes?
Distance = speed x time
D = (160 m/min) (20 min)
D = 3,200 m
What information does a Distance
vs. Time Graph show?
*Constant Speed:
speed that stays the same
Smith’s Trip to Albany
Distance (km)
Time (hr)
50
100
150
200
1
2
3
4
D 200
I
S 150
T 100
A
N 50
C
E
(km)
1
2
3
TIME (hours)
4
What information does a Distance
vs. Time Graph show?
*Speed
Changes
Brown’s Trip to Albany
Distance (km)
Time (hr)
100
100
150
200
1
2
3
4
D 200
I
S 150
T 100
A
N 50
C
E
(km)
1
2
3
TIME (hours)
4
What is velocity?
A measure of both
speed & direction
Example: An automobile travels 80 km North
in 2 hrs. What is the avg. speed of
the car? What is the avg. velocity?
V = D V = 80 km Avg. speed = 40 km/hr
2 hr Avg. velocity = 40 km/hr North
T
Date: 10/28/2007
Friday
Aim: 1. What does a distance vs. time graph
show?
2. How do velocities add & subtract
from each other?
Do Now: 1. Take out homework.
2. What is the slope of a distance vs. time graph
equal to?
Homework: Handout (A Speedy Journey)
20 km (40 km – 20 km)
0.5 h or 30 min
40 km (80 km – 40 km)
1.5 hrs.
5. What is car B’s
avg. speed during
the first part of
this trip?
Avg. S = T. Dist.
T. Time
Avg. S = 40 km
0.5 hr
Avg. S = 80 km/hr
6. How fast did cars A & B go together?
Avg. S = T. Dist.
Avg. S = 40 km
Avg. S = 40 km/hr
T. Time
1 hr
A = VF – VI
time
A = 0.67 – 0.60
10
A = 0.93 – 0.75
20
12 km / 20 s = 0.60 km/s
20 km / 30 s = 0.67 km/s
.007 km/s2
30 km / 40 s = 0.75 km/s
56 km / 60 s = 0.93 km/s
.009 km/s2
NO
Can velocities
add together?
Yes, but only if they’re moving
in the same direction
Example: If you are paddling
a boat South at 5 m/s & the
stream is moving at 8 m/s
South:
Are their velocities Your boat will move at:
adding together?
13 m/s South
Can velocities
subtract from
each other?
Yes, but only if they’re
moving in the opposite
direction
Example: If you are
paddling a boat South at 10
m/s & the stream is moving
North at 12 m/s:
Your boat will move:
2 m/s North
What does each picture show?
Velocities adding together
6 m/s Right
+
10 m/s Right
=
16 m/s Right
Velocities subtracting
10 m/s Right
-
14 m/s Left
=
4 m/s Left
Date: 10/17/2006
Wednesday
Aim: Lab: Measuring the Speeds of People
Walking
Do Now: 1. Take out homework.
2. Read over lab
3. Answer ques. next slide.
Homework: Complete Lab
Aim: How can we calculate acceleration?
Do Now: 1. Take out Lab & Motion Note-packet
2. Complete Review Questions on pg 6
in your note-packet
Homework:Handout
#1
#4
#1
None
All 4 cars are moving at constant speed
Avg. Speed = T. Dist./T. Time
__________=
250 km/hr 250 km/1 hr
What is
acceleration?
• The rate at which the
velocity of a moving
object increases
Acceleration =change in velocity
What is the
time
mathematical
formula for
OR
acceleration?
a = vfinal – vinitial
t
1) What is the acceleration of an ice skater
who changes velocity from 5 m/s north to 15
m/s north in 5 seconds?
a = 15 m/s – 5 m/s
a = vfinal – vinitial
5s
t
a = 2 m/s2 North
2) How quickly would a race car accelerate if
its velocity changed from 0 to 32 m/s in 4
seconds?
a = 32 m/s – 0 m/s
a = vfinal – vinitial
4s
t
a = 8 m/s2
What is
deceleration?
• The rate at which the
velocity of a moving
object decreases
What information does a Velocity vs.
Time Graph show?
*Constant acceleration
Smith’s Trip to Albany
Velocity (m/s)
Time (s)
7
14
21
28
1
2
3
4
V 28
E
L 21
O 14
C
I
7
T
Y
(M/S)
1
2
3
TIME (hours)
4
What is the motion
of a freely falling
object?
Any object falling near the surface
of the earth will accelerate at a
rate of 9.8 m/s2 due to the pull of
gravity.
Date: 10/19/2007
Friday
Aim: What is Momentum?
Do Now: Prepare for Motion Quiz
Homework: Study for next week’s Exam on
Motion & Forces
•Quiz (Motion)
• The mass of an object
What is
momentum? multiplied by its velocity, which
determines how difficult it is to
stop the object.
• The greater the momentum =
greater energy the object has
What is the
mathematical
formula for
momentum?
momentum = mass x velocity
or
p = mv
Date: 10/22/2007
Monday
Aim: 1. What is Force?
Do Now: 1. What 2 things does momentum
depend upon?
2. What are units of momentum?
Homework: Study for a Quiz on Forces.
What is a
Force?
A push or a pull that one object
exerts on another.
What are some examples of a force?
Ex) A tow truck pulls a car,
The wind pushes a flag,
Gravity & Friction
What is a
Newton?
The unit used to measure force
Force = Mass X Acceleration
1N = kg m/sec2
.
1. The attractive force
between objects
2. Depends on the masses of
the objects and the
distance between them
As mass increases, gravitational pull
increases
What is
gravitational
force?
As distance increases, gravitational
pull decreases
Where is the Gravitational Pull the
greatest?
1.
50 kg
10 m
2.
10 kg
10 m
10 kg
10 kg
Where is the Gravitational Pull the
greatest?
1.
2.
10 kg
10 kg
10 m
10 kg
20 m
10 kg
What is weight?
The weight of an object
is equal to the
gravitational force
exerted by Earth
(9.8m/s2) on an object
Where will you weigh more: on the
Earth or on the Moon? Why?
Forces on an object that
What are
balanced forces? are equal in size &
opposite in direction
=0
-
The net force is zero because the two forces
cancel each other out
What are
unbalanced
forces?
Unequal forces working
against each other produces
motion in the direction of
the larger force.
10N
4N
=
6N
*In Opposite Directions,
Forces Subtract
Date: 10/23/2007
Tuesday
Aim: 1. What is Newton’s First Law of Motion?
Do Now: Prepare for a Quiz.
Homework: Read pgs 98 – 103 &
Ans. Ques. (1-4 & 6-7) on pg 103 (self-check)
• Quiz (Momentum & Forces)
Newton’s Laws
of
Motion J
What is
Newton’s 1st
Law of
Motion?
The Law of Inertia
1. Objects at rest tend to stay
at rest unless acted upon by
an unbalanced force.
2. Objects in motion tend to
remain in motion (in constant
velocity, along a straight path)
unless acted upon by an
unbalanced force. (such as
friction)
This is what happens when your not wearing
a seatbelt. Since the car is in motion you are
also in motion, and when the wall stops the
car.You continue to be in motion and fly
forward.
When the truck is stopped by the
car. The ladder continues in
motion.
What is
inertia?
The tendency of an object to
resist a change in motion.
Inertia is related to an objects mass: the
more mass an object has the greater its
inertia and the more difficult it is to change
its motion.
Which would have more
inertia an empty shopping
cart or a full one?
Date: 10/24/2007
Wednesday
Aim: 1. What are 3 types of friction?
Do Now: 1. Take out homework.
2. What is Newton’s First Law of
Motion?
Homework: Read pgs 104-111 Ans. Ques. (1-4 &
6) on pg 111 (self check)
What is friction?
1. Exists wherever 2
surfaces touch.
2. It’s a force that acts
in the opposite
direction to motion.
3. It causes moving
objects to slow
down & stop.
4. It always produces
heat.
What types 1) Sliding Friction – When
of friction
solid objects slide over each
are there?
other.
2) Rolling Friction – Friction produced
by wheels or ball bearings
3) Fluid Friction – The force exerted by a
fluid (Lubricants such as grease & oil)
change sliding friction into fluid friction
and reduce the overall amount of friction.
1. Lubricants such as oil,
What are
grease, lotion, water
some
methods used 2. Wheels (Rolling frictions is
less than sliding friction)
to reduce
3. Sand on a smooth surface
friction?
Can friction
be good?
Yes!
In what direction is this object moving?
What are 3 forces are acting on this object?
Pull
Left 2N
(Friction)
Pull
Right 7N
How can we decrease the friction?
What is friction?
Date: 10/25/2007
Thursday
Aim: How do force, mass & acceleration relate to
each other?
Do Now: 1. Take out homework.
2. Describe the 3 types of friction.
Homework: Study for tomorrow’s Quiz on
Forces
What is
Newton’s
Second Law?
Newton’s second law of
motion explains how force
and acceleration are
related
What is the Force = Mass X Acceleration
equation
form of
F
Newton’s
second law?
M
A
Which car will take a greater force to accelerate?
How much force is needed to accelerate a
1500kg car at a rate of 3 m/sec/sec?
Force = mass x acceleration
Force = 1500kg x 3 m/sec/sec
Force = 4500N
F
M
A
A hockey player shoots a puck with a
force of 900 Newtons. The puck has a
mass of 1.5kg. At what rate will the puck
accelerate?
Acceleration =
Force
Mass
Acceleration = 900 N
1.5 kg
F
M
Acceleration = 600 m/s2
A
What is the
relationship
between force &
acceleration?
As force increases,
acceleration increases.
Direct Relationship
What is the
relationship
between mass &
acceleration?
As mass increases,
acceleration
decreases.
Inverse Relationship
Date: 10/26/2007
Friday
Aim: 1. What is Newton’s 3rd Law of Motion?
2. Quiz on Forces.
Do Now: Take out note-packet.
Homework: Study for Tuesday’s Motion/Forces
Exam
What is
Newton’s
Third Law of
Motion?
For every action
there is an equal and
opposite reaction.
Newton's third law. The skaters' forces on
each other are equal in magnitude, and in
opposite directions
• Newton’s Final Quiz
STOP
• Quiz Section Beyond This
Point
Quiz (Motion))
1. Velocity = ________ & ________.
2. A change in position over time is known as
_________.
3. If I rollerblade 10 meters in 2 seconds, how fast
am I moving?
4. If a car goes 20 km/hr in 0.5 hours how far did
it travel?
5. A car went from stop to 30 m/s in 5 seconds.
What was the rate of acceleration?
GO ON….
These graphs show:
6.
7.
GO ON….
8. Which car is moving
the fastest?
9. What pulls everything towards the earth
at a rate of 9.8 m/s2?
10.What tools are used to calculate speed?
Stop!!
Quiz (Momentum &Forces))
1. Momentum = ________ & ________.
2. A force = a ________ or a _________.
3. Units of force = ______________
4. As distance increases, gravitational pull
___________.
5. A book is resting (no motion) on the desk & is
pushing down with a force of 3N. The desk is
pushing up with a force of ________N.
STOP!!
What is a force?
What are balanced forces?
What do unbalanced forces cause?
What does friction create?
A force gives off ?
What are units of force?
What is a force that opposes motion?
STOP!!!