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Instructor’s Guide
Physics in Action
FORCES AND MOTION
Introduction
This Instructor’s Guide provides information to help you get the most out of Forces and Motion,
part of the five-part series Physics in Action. The contents of the guide will allow you to prepare your
students before using the program and to present follow-up activities to reinforce the program’s key
learning points.
Can the study of physics be fun? This clever five-part series answers “Yes!” by presenting essential
facts, formulas, and laws of physics through real-world examples, illustrative animations, and a likeable field guide named Mr. Physics who makes complicated concepts easier to understand. End-ofsection reviews are included throughout each program, and equations are worked out, step by step,
on-screen.
The series includes the following titles:
• Energy
• Forces and Motion
• Planets, Stars, and Galaxies
• Processes That Shape the Earth
• The Nature of Matter
Learning Objectives
After viewing the program, students will be able to:
• Calculate speed, distance, and acceleration
• Understand vectors and scalars
• Understand trajectory and g-force
• Define contact forces and action-at-a-distance forces
• Understand the relation of gravity to mass and weight
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Physics in Actions
FORCES AND MOTION
Instructor’s Guide
Educational Standards
BENCHMARKS FOR SCIENCE LITERACY STANDARDS
This program correlates with the following standards from Benchmarks for Science Literacy, by the
American Association for the Advancement of Science, for grades 9 through 12.
The Physical Setting: Motion
• Although the various forms of energy appear very different, each can be measured in a way that
makes it possible to keep track of how much of one form is converted into another. Whenever
the amount of energy in one place diminishes, the amount in other places or forms increases by
the same amount.
• The change in motion (direction or speed) of an object is proportional to the applied force and
inversely proportional to the mass.
• Whenever one thing exerts a force on another, an equal amount of force is exerted back on it.
• The energy of waves (like any form of energy) can be changed into other forms of energy.
• Any object maintains a constant speed and direction of motion unless an unbalanced outside
force acts on it.
The Physical Setting: Forces of Nature
• Gravitational force is an attraction between masses. The strength of the force is proportional to
the masses and weakens rapidly with increasing distance between them.
• Electric forces acting within and between atoms are vastly stronger than the gravitational forces
acting between the atoms. At larger scales, gravitational forces accumulate to produce a large and
noticeable effect, whereas electric forces tend to cancel each other out.
• At the atomic level, electric forces between electrons and protons in atoms hold molecules together
and thus are involved in all chemical reactions.
The Mathematical World: Symbolic Relations
• Sometimes the rate of change of something depends on how much there is of something else
(as the rate of change of speed is proportional to the amount of force acting).
• Symbolic statements can be manipulated by rules of mathematical logic to produce other statements of the same relationship, which may show some interesting aspect more clearly.
• Symbolic statements can be combined to look for values of variables that will satisfy all of them
at the same time.
• Tables, graphs, and symbols are alternative ways of representing data and relationships that can
be translated from one to another.
• When a relationship is represented in symbols, numbers can be substituted for all but one of the
symbols and the possible value of the remaining symbol computed. Sometimes the relationship
may be satisfied by one value, sometimes by more than one, and sometimes not at all.
SOURCE: Benchmarks For Science Literacy, by The American Association for the Advancement of Science. Copyright 1993,
2009 by The American Association for the Advancement of Science. Used by permission of Oxford University Press, Inc.
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Physics in Actions
FORCES AND MOTION
Instructor’s Guide
ENGLISH LANGUAGE ARTS STANDARDS
The activities in this instructor’s guide were created in compliance with the following standards
from National Standards for the English Language Arts, from the National Council of Teachers of
English.
• Students adjust their use of spoken, written, and visual language (e.g., conventions, style, vocabulary)
to communicate effectively with a variety of audiences and for different purposes.
• Students employ a wide range of strategies as they write and use different writing process elements
appropriately to communicate with different audiences for a variety of purposes.
• Students conduct research on issues and interests by generating ideas and questions, and by posing
problems. They gather, evaluate, and synthesize data from a variety of sources (e.g., print and nonprint texts, artifacts, people) to communicate their discoveries in ways that suit their purpose and
audience.
• Students use a variety of technological and information resources (e.g., libraries, databases,
computer networks, video) to gather and synthesize information and to create and communicate
knowledge.
• Students use spoken, written, and visual language to accomplish their own purposes (e.g., for
learning, enjoyment, persuasion, and the exchange of information).
SOURCE: Standards for the English Language Arts, by the International Reading Association and the National Council
of Teachers of English. Copyright 1996 by the International Reading Association and the National Council of Teachers of
English. Reprinted with permission.
TECHNOLOGY STANDARDS
The activities in this instructor’s guide were created in compliance with the following standards from
The ISTE National Education Technology Standards (NETS•S) and Performance Indicators for
Students.
• Creativity and Innovation: Students demonstrate creative thinking, construct knowledge, and
develop innovative products and processes using technology.
• Research and Information Fluency: Students apply digital tools to gather, evaluate, and use
information.
• Critical Thinking, Problem Solving, and Decision Making: Students use critical thinking skills
to plan and conduct research, manage projects, solve problems, and make informed decisions
using appropriate digital tools and resources.
SOURCE: © 2007 The International Society for Technology Education. Reprinted with permission.
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Physics in Actions
FORCES AND MOTION
Instructor’s Guide
Program Overview
In New York City, there are many ways to travel. Of course, it’s a lot easier if you’re a bird. Using the
Big Apple as a living laboratory, this program addresses speed and distance using a pigeon, a taxi, and
a tour boat. Additional situations such as the deployment of a Mars rover, a zero-G flight in NASA’s
Weightless Wonder, a walk on a conveyor belt and a cruising aircraft carrier, and juggling on the Earth
and around the Solar System provide opportunities to study the mechanics of velocity and acceleration
as well as contact forces and forces that act at a distance. Vector algebra is demonstrated throughout.
Main Topics
Chapter 1: Calculating Speed and Distance
Using the examples of a pigeon, a taxi, and a tour boat circling Manhattan, the program begins by
explaining how to calculate speed and distance, taking into account both path length and displacement. Also covered: dimensions, units, and conversion factors.
Chapter 2: Speed and Acceleration
The deployment of a Mars rover is used to illustrate concepts of acceleration and speed. Also covered:
using a diagram, chart, or graph to track position over time.
Chapter 3: Vectors: Motion in the Three Dimensions
Here Mr. Physics explains vectors and scalars, and how they are used to describe, in mathematical
terms, movement and direction.
Chapter 4: Accelerated Motions
NASA’s “Weightless Wonder” — aka the Vomit Comet — is featured in this discussion of trajectory,
parabolas, and g-force.
Chapter 5: Forces
This section discusses contact forces, such as friction and tension, and action-at-a-distance forces,
such as electromagnetism. The relation of gravity to mass and weight is explained as Mr. Physics
weighs a juggling pin on Earth, the Moon, and Jupiter. Point mass and force-body diagrams are also
covered.
Chapter 6: Forces and Accelerations
The program’s final section explores the relationship between forces and motion, and points out that
understanding the law of conservation of momentum is useful for modeling the results of impacts
and explosions.
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Physics in Actions
FORCES AND MOTION
Instructor’s Guide
Fast Facts
• The constant average speed of a Mars rover heading toward its destination is an amazing 31,500
meters per second.
• Scientists use the term ‘acceleration’ for any change in speed, whether it’s speeding up or slowing
down.
• Scalars are quantities which can be described in terms of magnitude or numerical value, such as
time, mass, and temperature. Vectors are quantities which are described by both a magnitude and
a direction.
• The concepts of ‘distance’ and ‘displacement’ are similar. But distance is a scalar quantity that
describes how much ground an object has covered during its motion; and displacement is a vector
quantity that describes an object’s overall change in position.
• As part of astronaut training, NASA uses special aircraft capable of providing a nearly weightless
environment. A state of free fall is achieved by following a flight path that is elliptical in relation
to Earth’s center; the craft does not exert any g-forces on the astronauts. NASA calls this aircraft
the ‘Weightless Wonder,’ but for reasons you can imagine, it’s more commonly known as the
‘Vomit Comet.’
• Whether it’s a cannonball, a stream of water, or a plane that cuts its engines, objects hurtled
through the air will all take roughly the same path (the shape of that path is called a parabola).
• Creators of computer games and special effects in movies use the principles of physics to create
realistic-looking explosions. Smoke, flames, and clouds of debris act a lot like their real-life counterparts due to software that calculates speed and direction. When virtual people fall over dead, software
using ‘ragdoll physics’ has calculated the effect of gravity on the body, and how different body parts
would move as the body slumps or falls down.
• The idea that a free particle takes the quickest path between its starting and ending points is called
the ‘principle of least time.’ Ancient Greek and Arab scientists stated this principle for paths of rays
of light. In the 20th century Albert Einstein demonstrated that a parabola could be the shortest
path between two points when space and time were curved in the presence of gravity.
• We categorize forces as being either ‘contact’ (where the interacting objects touch) or ‘action-at-adistance’ (where they don’t). But if we look deep into the small-scale structure of matter, the concept
of objects touching loses its meaning. Actually, all contact forces are the result of electromagnetism,
which is an action-at-a-distance force.
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Physics in Actions
FORCES AND MOTION
Instructor’s Guide
Vocabulary Terms
acceleration: The vector which gives the direction of, and the instantaneous rate at which velocity
changes with time.
action-at-a-distance-force: A fundamental force of nature that is seemingly transmitted over
empty space; that is, the interacting objects do not touch. Examples include electromagnetic forces,
the weak force (changes subatomic particles from one kind to another), the strong force (holds the
atomic nucleus together), and gravity.
average speed: The straight-line distance between the end-points of a motion, divided by its duration
in time.
contact force: A nonfundamental force of nature that can be traced to the physical touching of two
objects. Examples include friction, fluid resistance, tension, spring force, and buoyant force.
dimension: The type of physical property that a number or variable represents. Examples include
length, mass, and time.
displacement: The vector that joins two subsequent positions of an object; an object’s overall
change in position.
distance: A scalar quality which refers to the extent or amount of space between points.
force: An influence that, if applied to a free body, results in an acceleration of that body.
force-body diagram: A technique of making a simplified drawing of the individual force vectors
acting on an object.
g-force: A force acting on a body as the result of acceleration or gravity; a force experienced by a body
which is its acceleration relative to free-fall. (Technically, g-force is not a force, but an acceleration.)
inertia: The property of matter by which it retains its state of rest or its velocity along a straight
line so long as it is not acted upon by an external force.
parabola: A geometrical shape consisting of a single bend and two lines going off to an infinite
distance. A parabola is the trajectory that most objects take as they fly unpowered through the air.
path length: The length of the actual, physical path traversed by an object (as opposed to the
straight-line distance between the endpoints).
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Physics in Actions
FORCES AND MOTION
Instructor’s Guide
point mass: A hypothetical object in which all the physical bulk is concentrated in a tiny, pointsized location.
scalar: A quantity which is described by magnitude (or numerical value) alone; a number or
algebraic symbol that has a size, but no direction. Time, mass, and temperature are all examples of
scalars.
trajectory: The path of an object moving through space.
vector: A quantity that is fully described by both magnitude and direction.
velocity: The vector which gives the directon of and the instantaneous rate at which the displacement of an object changes with time.
Pre-Program
Discussion Questions
1. What do you think is the difference between ‘distance’ and ‘displacement’?
2. When launching a missile into space, do scientists simply point it in a certain direction? With no one
steering, what factors do you think come into play to ensure a Mars rover makes it from the launching pad to Mars?
3. What is the difference between velocity and acceleration?
4. What are “forces at a distance”?
5. Why is time considered to be a dimension?
Post-Program Discussion Questions
1. What is path length? What is displacement?
2. What is the difference between a vector and a scalar?
3. After viewing the program, can you explain the difference between distance and displacement?
4. What is g-force?
5. What is the law of conservation of momentum?
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Physics in Actions
FORCES AND MOTION
Instructor’s Guide
Student Projects
• The basic idea behind quantum mechanics is that when an action is performed on a certain
particle, another particle with which is it ‘entangled’ will respond — even if the two particles are
miles apart. Using the library and Internet, research and report on quantum mechanics. What
did Einstein mean when he called it ‘spooky action-at-a-distance’? What everyday applications
do scientists foresee for quantum mechanics? (Visit Web sites such as www.livescience.com,
www.sciencentral.com, and www.popsci.com [Popular Science] for ideas and information.)
• Using terms such as g-force, acceleration, velocity, and free fall, create an illustrated report
explaining the physics behind a roller coaster ride, cliff diving, and skateboarding.
• Create a chart with information on contact forces. Columns should include the name of the
force (e.g., ‘frictional’); its symbol (e.g., Ff ); how it works (e.g., when two surfaces are in close
contact, the molecules of each pull and push laterally against each other); and some things that
this force does (e.g., allows car brakes to work, enables us to walk instead of staying in place).
•
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Physics in Actions
FORCES AND MOTION
Instructor’s Guide
Assessment Questions
1. F
or a taxi to drive from one corner of Central Park to the other, it will have to stay on the roads.
If we want to calculate the taxi’s average speed along its route, we use the taxi’s _____ rather than
displacement.
a) acceleration divided by amount of time traveled
b) amount of time traveled divided by acceleration
c) path length
d) path speed
2. Average acceleration is change in speed divided by change in _____.
a) average speed
b) time
c) velocity
d) trajectory
3. ‘80 miles east’ is an examle of a [scalar / vector]. ‘256 bytes’ is an example of a [scalar / vector].
‘150 calories’ is an example of a [scalar / vector].
4. T
rue or False? A cannonball, a stream of water, and a plane that cuts its engines will hurtle
through the air in either a shallow curve or a straight line, depending on the weight of the object.
5. What concept helps physicists calculate the motion of an object moving from planet to planet,
and thus changing its weight?
a) Point mass
b) A force-body diagram
c) Conservation of motion
d) Action-at-a-distance force
6. Fluid resistance is an example of a(n) [contact force / action-at-a-distance force]. Electromagnetism is an example of a(n) [contact force / action-at-a-distance force]. Tension is an example
of a(n) [contact force / action-at-a-distance force]. Gravity is an example of a [contact force /
action-at-a-distance force].
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Physics in Actions
FORCES AND MOTION
Instructor’s Guide
7. [Mass / weight] is constant, but [mass / weight] is proportional to gravity.
8. The definition of ‘momentum’ is ‘mass times _____.’
a) weight
b) speed
c) velocity
d) inertia
9. True or False? According to the Law of Conservation of Momentum, if two objects collide in the
absence of outside force, momentum would not be lost.
10. Net forces cause _____.
a) conservation of momentum
b) speed
c) velocity
d) acceleration
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Physics in Actions
FORCES AND MOTION
Instructor’s Guide
Assessment Questions Answer Key
1. F
or a taxi to drive from one corner of Central Park to the other, it will have to stay on the roads.
If we want to calculate the taxi’s average speed along its route, we use the taxi’s _____ rather than
displacement.
a) acceleration divided by amount of time traveled
b) amount of time traveled divided by acceleration
c) path length
d) path speed
A: (c) path length
2. Average acceleration is change in speed divided by change in _____.
a) average speed
b) time
c) velocity
d) trajectory
A: (b) time
3. ‘80 miles east’ is an examle of a [scalar / vector]. ‘256 bytes’ is an example of a [scalar / vector].
‘150 calories’ is an example of a [scalar / vector].
A: ‘80 miles east’ is an examle of a vector. ‘256 bytes’ is an example of a scalar. ‘150 calories’ is an
example of a scalar.
4. T
rue or False? A cannonball, a stream of water, and a plane that cuts its engines will hurtle
through the air in either a shallow curve or a straight line, depending on the weight of the object.
A: False. Whether it’s a cannonball, a stream of water, or a plane that cuts its engines, objects hurtled
through the air will take roughly the same path. The shape of that shape is called a parabola.
5. What concept helps physicists calculate the motion of an object moving from planet to planet,
and thus changing its weight?
a) Point mass
b) A force-body diagram
c) Conservation of motion
d) Action-at-a-distance force
A: (a) Point mass
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Physics in Actions
FORCES AND MOTION
Instructor’s Guide
6. Fluid resistance is an example of a(n) [contact force / action-at-a-distance force]. Electromagnetism is an example of a(n) [contact force / action-at-a-distance force]. Tension is an example
of a(n) [contact force / action-at-a-distance force]. Gravity is an example of a [contact force /
action-at-a-distance force].
A: Fluid resistance is an example of a contact force. Electromagnetism is an example of an action-at-adistance force. Tension is an example of a contact force. Gravity is an example of an action-at-adistance force.
7. [Mass / weight] is constant, but [mass / weight] is proportional to gravity.
A: Mass is constant, but weight is proportional to gravity.
8. The definition of ‘momentum’ is ‘mass times _____.’
a) weight
b) speed
c) velocity
d) inertia
A: (c) velocity
9. True or False? According to the Law of Conservation of Momentum, if two objects collide in the
absence of outside force, momentum would not be lost.
A: True.
10. Net forces cause _____.
a) conservation of momentum
b) speed
c) velocity
d) acceleration
A: (d) acceleration
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Physics in Actions
FORCES AND MOTION
Instructor’s Guide
Additional Resources
ScienCentral
Science Videos, Science News
www.sciencentral.com
Physics.org
Your guide to physics on the web
www.physics.org
Institute of Physics.org
www.iop.org
Scientific American
www.sciam.com
Popular Science
www.popsci.com
LiveScience
www.livescience.com
ScienceDaily
Your source for the latest research news
www.sciencedaily.com
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Physics in Actions
FORCES AND MOTION
Additional
Instructor’s Guide
Products from Films Media Group
Available from Films Media Group • www.films.com • 1-800-257-5126
All About Motion: Displacement, Velocity, and Acceleration (DVD/VHS)
With crystal-clear graphics and calculation examples, this program introduces concepts of scalar
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Principles and Laws of Motion (DVD/VHS)
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Physics in Actions
FORCES AND MOTION
Instructor’s Guide
Everyday Einstein: Einsteinian Physics at Work and at Play (DVD/VHS)
In 1905, Albert Einstein released a series of groundbreaking papers on relativity, quantum theory, and
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Original CBC broadcast title: Everyday Einstein. (45 minutes) © 2006 (# 39384)
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1st Law Poster | Newton’s 2nd Law Poster | Newton’s 3rd Law Poster. © 2008 (# 38992)
Please send comments, questions, and suggestions to [email protected]
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