Transcript Force - TeacherWeb

Chapter 12
Force
Force Vocabulary
FORCE- A push or pull.
BALANCED Forces that are equal in size, but
FORCES- opposite in direction.
UNBALANCED Forces that cause a change in the
motion of an object.
FORCES-
Force Vocabulary
GRAVITY- Force of attraction between all
objects in the universe.
NEWTON- SI unit of force.
WEIGHT- Measure of the force of gravity
acting on an object.
MASS- The amount of matter in an object.
Force Vocabulary
FRICTION-
STATIC
FRICTION-
Force that opposes the motion of an object.
Occurs when objects are not moving.
SLIDING
FRICTION- Occurs when 2 objects slide past each other.
ROLLING
FRICTION-
Occurs when 2 objects roll past each other.
AIR
RESISTANCE- An upward push as an object falls.
Force Vocabulary
LUBRICANTS- Materials that reduce friction.
Key Topic is…
What is Force?
Our Objective is…
Define force and give examples of
forces in nature.
Identify balanced and unbalanced
forces and describe their effects.
1st Main Idea…
Force
 A ________ is
_________________________.
 A ______ always
___________________________.
 If the force is _________ __________,
the object _____ ______ in the
________________________.
Force
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?
?
PUSH
PULL
Courtesy:tugfest.com
Ch. 12 Force
Sec 12-1
2nd Main Idea…
Balanced Forces
 To _______ a force, you must
________________.
 1.
 2.
______ forces are _____________________
and ______________________.
_________ forces do not
Examples!!
25 N
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25 N
Balanced Forces-No Movement
Force
3rd Main Idea…
Unbalanced Forces
 _________ forces cause
___________________
____________________.
Ch. 12 Force
25 N
Sec 12-1
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10 N
UnBalanced Forces-Movement
Force
4th Main Idea…
Forces & Motion
 ________ forces can ______________
_______________________.
 1.
 2.
5th Main Idea…
Forces In Nature
Examples of forces you experience
everyday:
 _________- a measure of _________
between ________________________.
 _______ force- attraction of a
__________________________________.
 _____ force-moving _________________.
 Falling ______ is caused by
________________.
Force
http://www.milfordroad.co.nz/images/avalanche.jpg
http://www.lcpu.org/images/windy-day.jpg
https://www.forcefieldmagnets.com/catalog/images/cat_magnets.jpg
http://www.codinghorror.com/blog/images/waterfall.jpg
Force – Part 2
Key Topic is…
What is Gravity?
Our Objective is…
Explain Newton’s
laws of gravity.
Force – Part 2
1st Main Idea…
Sir Isaac Newton
 ________ hypothesized that there is a
________ called _________ that makes
_________________________________
______.
 Newton’s law of Universal Gravitation_________________________________
_________________________________
_________________________________.
Ch. 12 Force
Sec 12-2
2nd Main Idea…
Gravity
 _______ is a _____________________
between ________________________.
 ____ _________ on or near
_________________ are ________
toward __________________________
_________________________________.
Force – Part 2
3rd Main Idea…
Gravity & Mass
 The amount of ____________________
between ____ _________ depends on
____________________________________
________.
 When an apple falls, they both
_________________________________.
 However, because___________________
than the ______, the Earth_____________.
Force – Part 2
4th Main Idea…
Gravity & Distance
 The ____________________________
between _________________________
as the __________________________.
Force – Part 2
Forces – Part 2
1. DESCRIBE: In which direction does
an object fall on Earth?
2. EXPLAIN: Why is the force of Earth’s
gravity so strong?
Force – Part 3
Key Topic is…
How does a Spring Scale Work?
Our Objective is…
Describe how a spring scale is used
to measure weight.
Force – Part 3
1st Main Idea…
The SI Unit of Force
 The _______ is the ________________.
 On Earth, ________________________
to lift a __________________________.
 ________ is a measure of the
_________________________________.
 Because it is a ______, the object’s
________ is measured in _________(N).
Force Part 3
2nd Main Idea…
Using a Spring Scale
 A ________ ________ measures the
_________________________________
____________; this is also called its
_________________.
Force – Part 3
3rd Main Idea…
Types of Spring Scales
 There are ______ _____ of _______
_________.
Ex. Lab scales, bathroom scales &
market scales.
 Weight pushes or pulls on a _______
causing a dial or pointer to turn until it
shows the _______ of the object.
Ch. 12 Force
Sec 12-3
Force – Part 3
1. IDENTIFY: What are you measuring
when you weigh an object?
2. IDENTIFY: What does a spring scale
measure?
3. What are three types of spring
scales?
Force – Part 4
Key Topic is…
What is Friction?
Our Objective is…
Identify examples of friction.
Ch. 12 Force
Sec 12-4
1st Main Idea…
Forces & Motion
 To stop a _______ ________, a _______
must act in the __________________to
the direction of the __________.
 Observe: Give your book a slight push.
What happens? __________________.
 What must you do to keep it moving?
________________________________.
Force – Part 4
http://ffden2.phys.uaf.edu/211_fall2002.web.dir/Ben_Towns
end/StaticandKineticFriction.htm
http://www.school-forchampions.com/science/friction.htm
Ch. 12 Force
Sec 12-4
2nd Main Idea…
Friction
• _______ is a_______________________
____________________________.
Force – Part 4
3rd Main Idea…
Types of Friction
Types of friction when there is contact
between surfaces:
 _______ friction, a book ____________.
 ______ friction, a book _____________.
 ______ friction, contact between bike
________.
 ___ __________ (Fluid friction) pushes
_______ _______________ as it falls.
Force – Part 4
Force – Part 4
Force – Part 4
Force – Part 4
Force – Part 4
4th Main Idea…
Useful Friction
 _______ makes ___________________.
 Without ___________, you would not
be able to ___________________,
_______________, _________________,
or ___________________.
Force – Part 4
5th Main Idea…
Harmful Friction
 Unwanted _________ can be found in
________ ___________________.
 _______ _____ rub together and
______ ______ and can cause
__________________________.
Ch. 12 Force
Sec 12-4
Force – Part 5
Key Topic is…
How can friction be changed?
Our Objective is…
Describe some ways to change
friction.
Force – Part 5
1st Main Idea…
Moving Against Friction
 Because friction
_______________________ to move
_______, ______________ is needed to
_________________________________.
Ch. 12 Force
Sec 12-5
2nd Main Idea…
Using Rolling Friction
 One way to _______ ________ is to
__________ ________ ________ to
_____________________.
 _______ friction is
________________________ friction.
Force – Part 5
3rd Main Idea…
Using Lubricants
 __________ are ___________________.
 ____ is a ____________ that ________
________________________ from one
another.
Force – Part 5
4th Main Idea…
Not Enough Friction
 Slipping on an icy sidewalk or a
____________ _____________ are
examples of when there is
_______________________________
surfaces.
 To ________ ________ we sometimes
_______ _______ on an _____ _____ or
wear special __________________.
Force – Part 5
www.superiorspecialty.com/. ../Incom/GritE.html
Force – Part 5
1. CALCULATE: If the force of friction
is 16 N, how much force is needed to
move the object?
2. IDENTIFY: When would it be helpful
to use a lubricant?
3. HYPOTHESIZE: Why do staircases
often have rubber mats on the steps?