Transcript Chapter 3 Notes PowerPoint

CHAPTER 3 NOTES
FORCES & MOTION
GRADE 7, CHAPTER 3
SCIENCE STARTERS FOR
MONDAY, OCTOBER 12, 2015
1. Motion
2. Reference point
3. International system
of units
4. distance
A. the measurement
system used by
scientists.
B. the length of the path
between two points
C. changing position
relative to another
object.
D. a place or object used
for comparison to
determine if an object is
in motion.
SCIENCE STARTERS FOR
TUESDAY, OCTOBER 13, 2015
SCIENCE STARTERS FOR
WEDNESDAY, OCTOBER 14, 2015
1. average speed
2. velocity
3. instantaneous speed
4. slope
5. speed
A. the distance an object
moves per unit of time.
B. total distance divided by
total time
C. speed at a given point
in time
D. speed in a given
direction
E. the steepness of a line
on a graph.
BINDER
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After TAB 3
Blue Science Starters
Chapter Organizer
Chapter 3 notes
Motion Organizer
Vocab Foldable
VOCAB FOLDABLE
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Motion
Reference point
International system of units
Distance
Speed
Average speed
Instantaneous speed
Velocity
Slope
acceleration
SCIENCE STARTERS FOR
THURSDAY, OCTOBER 15, 2015
SCIENCE STARTERS FOR
TUESDAY, OCTOBER 20, 2015
• TRUE OR FALSE.
1. If a train is slowing down, it is accelerating.
2. To find the acceleration of an object moving in a straight line,
you must calculate the change in distance for each unit of
time.
3. A Ferris wheel turning at a constant speed of 5 m/s is not
accelerating.
4. An airplane is flying west at 200 km/h. Two hours later, it is flying
west at 300 km/h. Its average acceleration is 100 km/h2.
5. The SI units for acceleration are km/h2.
SCIENCE STARTERS FOR
WEDNESDAY, OCTOBER 21, 2015
1. The rate at which the velocity of an object changes is the object’s
rate of _______________.
2. An airplane is accelerating at 8 m/s2. Each second its speed
increases by _____________ m/s.
3. An airplane is accelerating at -8 m/s2. The distance the airplane
travels each second is _________ than the distance it traveled
during the previous second.
4. An amusement park ride falls straight down for 4 seconds. During
this time, the ride accelerates from a speed of 0 m/s to 40 m/s/ The
ride’s rate of acceleration during the 4 seconds is _____________
m/s2.
SCIENCE STARTERS FOR
THURSDAY, OCTOBER 22, 2015
1. newton
A. the SI unit for force
2. Force
B. sum of all forces acting
on an object.
3. balanced forces
C. push or pull
4. unbalanced forces
5. net force
D. can change an object’s
motion.
E. will not change an
object’s motion.
SCIENCE STARTERS FOR
FRIDAY, OCTOBER 23, 2015
1. When you pull on a window shade, you exert a(n) ______.
2. A(n) _______ can be used to represent the direction and strength of
a force.
3. The strength of a force is measured in ________.
4. The net force determines how and if an object will _______.
5. When two forces act in opposite directions, the object will accelerate
in the same direction as the _______ force.
6. A force is described by its ____ and by the direction in which it acts.
SCIENCE STARTERS FOR MONDAY,
OCTOBER 26, 2015
• Newton’s second law of motion states that an
object’s acceleration depends on its _______ and
on the net force acting on it.
• Acceleration is measured in __________.
• Force is measured in a unit called the _________.
• The smaller the mass of an object, the _________ its
inertia.
SCIENCE STARTERS FOR TUESDAY,
OCTOBER 27, 2015
• Newton’s 1st, 2nd, or 3rd Law of Motion
• A train stops suddenly at the train station and everyone in
the cars continue moving forward.
• A teacher sitting in her rolling chair pushes against the wall
and moves in the opposite direction.
• A model rocket flies upwards as the engine combusts and
creates a force towards the Earth.
• A rollercoaster takes off quickly and everyone’s head is
thrown backwards towards the headrest.
SCIENCE STARTERS FOR WEDNESDAY,
OCTOBER 28, 2015
Newton’s 1st, 2nd or 3rd Law?
• If a bowling ball and a basketball are rolled with the
same amount of force, the basketball will accelerate
faster.
• A shotgun is fired and the ‘kick’ of the gun injures a
person’s shoulder.
• A semi-truck and a small car are traveling at the same
speed. They each hit the brakes at the same time but it
takes much longer for the truck to slow down.
• A magician quickly pulls a table cloth out from under a
set of dishes. The dishes remain in the same spot.
SCIENCE STARTERS FOR THURSDAY,
OCTOBER 29, 2015
True or False.
• Newton’s first law of motion states that an object will not
experience a change in motion unless acted upon by a
balanced force.
• To increase acceleration of an object, you reduce its
mass or increase the applied force.
• Newton’s third law of motion states that if one object
exerts a force on another object, then the second
object exerts a force of equal strength in the same
direction.
• Resistance to change in motion is called stasis.
SCIENCE STARTERS FOR FRIDAY,
OCTOBER 30, 2015
• Steve Spangler Halloween Videos
SCIENCE STARTERS FOR MONDAY,
NOVEMBER 2, 2015
• NO ACTUAL SCIENCE STARTERS ~ Make sure your
binder is set up correctly (see below).
• HOMEWORK: Check your power school tonight! I
have a TON of no name papers!
After TAB 3
Blue Science Starters
Chapter Organizer
Chapter 3 notes
Motion Organizer
Vocab Foldable 1 & 2
Race Car Graphing
Graphing Stations
Newton’s Laws Stations
Golf Lab
SCIENCE STARTERS FOR TUESDAY,
NOVEMBER 3, 2015
• TEST ON THURSDAY!!!
• The factors that affect the gravitational force
between two objects are ________ and ______.
• Newton’s second law states that force is equal to
_______________.
• A change in position relative to a reference point is
__________.
SCIENCE STARTERS FOR THURSDAY,
NOVEMBER 5, 2015
• Put SPACES between the desks.
• BRING something to work on after the test.
• Turn in GOLF LAB into your class period’s tray.
• Write TEST on your Science Starter for today.
• There is NO BINDER CHECK TODAY!
• STUDY until class starts.
I HAVE A TON OF NO NAME PAPERS!!
• Please check the no name papers if your name is
on this list!!!!
PD.2 ~
• Sophia Palacios (2)
• Rayna Boggs
• Makenna Boles
• Lelah Davidson
• Morganna Semler
• Evan Sickafoose
DESCRIBING MOTION
Nicolaus Copernicus
In 1543 Copernicus published On the Revolution of the Heavenly
Spheres, a book based on his 30-year study of the solar system.
MOTION
• An object is in MOTION if its position changes in relation
to another object.
• A REFERENCE POINT is a place or object used for
comparison to determine if something is in motion.
• An object is in motion if it changes position relative
to a reference point.
MEASURING DISTANCE
• Scientists use a system of
measurement called the
INTERNATIONAL SYSTEM OF
UNITS (SI).
• DISTANCE is the length of the
path between two points.
• The SI UNIT for measuring
distance is the METER.
SPEED
• The SPEED is the distance the object moves per unit of
time.
• To calculate the speed of an object, divide the distance
the object travels buy the amount of time it takes to
travel that distance.
• Speed = distance
time
SPEED
• To calculate AVERAGE SPEED, divide the total distance
traveled by the total time.
• INSTANTANEOUS SPEED is the speed at which an
object is moving at a given instant in time.
SPEED AND VELOCITY
Use the data from all three
legs to solve for each
triathlete’s average speed.
VELOCITY
• VELOCITY is speed in a given direction.
• An error in determining a velocity, either in speed or
in direction, could lead to a collision.
GRAPHING MOTION
• You can show the motion of an object on a line graph in
which you plot distance versus time.
• The steepness of a line on a graph is called SLOPE.
• Calculating Slope:
•
• Slope=
Rise
Run
SPEED AND VELOCITY
Constant Speed
What is the jogger's speed?
SPEED AND VELOCITY
Changing Speed
The graph shows how the speed of a jogger varies during her second day of
training. What are the rise, the run, and the slope for each segment of the graph?
ACCELERATION
• ACCELERATION is the rate at which velocity changes.
• In science, acceleration refers to increasing speed,
decreasing speed, or changing direction.
•
• Acceleration =
Final Speed – Initial Speed
Time
ACCELERATION
Acceleration
The airplane is accelerating at a rate of 8 m/s2. Determine the speed of the
airplane at 4.0 s and 5.0 s.
0 m/s 8 m/s
16 m/s
24 m/s
ACCELERATION
Deceleration
The airplane touches down with a speed of 70 m/s. It decelerates at a
rate of -5 m/s2. Determine its speed after each second of its
deceleration.
FORCE
• A FORCE is a push or pull.
• Like velocity and acceleration, a force is described by its
strength and by the direction in which it acts.
• The strength of a force is measured in the SI unit called
the NEWTON (N), after scientists Sir Isaac Newton.
NET FORCE
• The NET FORCE is the combination of all the forces on
an object.
• A nonzero net force causes a change in the object’s
motion.
THE NATURE OF FORCE
Net Force
The change in motion of an object
is determined by the net force
acting on the object. What is the
net force for each situation?
THE NATURE OF FORCE
Which of these three arrows represents the correct amount of net force
of the above two arrows?
FRICTION & GRAVITY
• FRICTION is the force that two
surfaces exert on each other when
they rub against each other.
• Two factors that affect the force of
friction are the types of surfaces
involved and how hard the surfaces
are pushed.
FRICTION & GRAVITY
Types of Friction
Friction acts opposite the direction of motion. Determine the frictional force at
work.
FRICTION & GRAVITY
Frictions
Give five examples for sliding, static, fluid, and rolling frictions.
UNIVERSAL GRAVITATION
• GRAVITY is the force that pulls
objects toward each other.
• UNIVERSAL GRAVITATION is
the law that states that the force
of gravity acts between all objects
in the universe that have mass.
• Two factors that affect the
gravitational attraction between
objects are mass & distance.
UNIVERSAL GRAVITATION
• MASS is a measure of the amount of matter in an object.
• The more mass on object has, the greater the
gravitational force between it and other objects.
• Gravitational force also depends on the distance
between the objects’ centers.
FRICTION & GRAVITY
Gravitational
Attraction
Gravitational
attraction depends
on two factors:
mass and
distance. Compare
the gravitational
force between
different planets
and their sun.
WEIGHT
• WEIGHT is a measure of the force of gravity on an
object.
FRICTION & GRAVITY
Weight and Mass
The Mars Phoenix Lander weighs about 3,400 N on Earth. It weighs about
1,300 N on Mars. If the dog weighs 60 N on Earth, what would he weigh
on Mars and the moon?
NEWTON’S FIRST LAW OF MOTION
The First Law of Motion states that an object at
rest will remain at rest unless acted upon by a
nonzero net force. An object moving at a
constant velocity will continue moving at a
constant velocity unless acted upon by a
nonzero net force.
INERTIA is the resistance to change in motion.
NEWTON’S SECOND LAW OF MOTION
• The Second Law of Motion states that an objects
acceleration depends on its mass on the net force acting
on it.
• Acceleration =
Net force
mass
• Net force = Mass x Acceleration
NEWTON’S SECOND LAW OF MOTION
Newton’s Second Law
Suppose that four dogs pull a sled carrying two people. How can the
picture-stories be completed to represent answers to the two different
questions?
NEWTON’S THIRD LAW OF MOTION
• The Third Law of Motion states that if one object exerts a
force on another object, then the second object exerts a
force of equal strength in the opposite direction of the
first object.
ACTION REACTION
Action-Reaction Forces
How can the illustration of the dogs be completed to represent
Newton's Third Law of Motion?
WHAT MAKES A BUG GO SPLAT?
What Makes a
Bug Go Splat?
Splat! A bug
has just flown into the
windshield of
an oncoming
car. The car
must have hit
the bug much harder
than the bug hit
the car, right?