Download Opportunities for Expository or Explanatory writing

Realigned 9th Grade Physics Program Guide (Semester 1)
Enduring Understandings & Essential Questions
Energy, Waves & Electricity
(8/15/08)
Overarching Enduring Understandings:
Every process in the universe involves the transfer or transformation of energy. The amount of energy in the universe is
constant.
Overarching Essential Questions:
 What is energy?
 How much energy is there in the Universe?
 How does energy get from one place to another?
Primary State Content Standards Addressed in the Unit – Components & GLE’s
Component 1.1 Properties: Understand how properties are used to identify, describe, and categorize substances, materials, and objects and
how characteristics are used to categorize living things.
1.1.3 Wave Behavior: Understand sound waves, water waves, and light waves using wave properties, including amplitude, wavelength,
and speed. Understand wave behaviors, including reflection, refraction, transmission, and absorption.
1.1.4 Forms of Energy: Understand that energy is a property of matter, objects, and systems and comes in many forms (i.e. heat
(thermal) energy, sound energy, light energy, electrical energy, kinetic energy, potential energy, and chemical energy).
Component 1.2 Structures: Understand how components, structures, organizations, and interconnections describe systems.
1.2.1 Structure of Systems: Analyze how systems function, including the inputs, outputs, transfers, transformations, and feedback of
a system and its subsystems
1.2.2 Energy Transfers and Transformations: Understand how various factors affect energy transfers and that energy can be
transformed from one form of energy to another.
Component 2.1 Investigating Systems: Develop the knowledge and skills necessary to do scientific inquiry.
Component 2.2 Nature of Science: Understand the nature of scientific inquiry.
1
9th Grade Physics Program Guide
SUB-Section #1: Energy, and Energy Transfers &
Topical Enduring Understanding: Everything we see, hear,
Transformations
or do involves some form of Energy. Energy is what makes
(3 weeks OR LESS—Based on students’
things happen.
entering knowledge from Middle School)
Key Ideas and Enabling Knowledge
GLE References:
1.1.4 Forms of Energy
1.2.1 Structure of Systems
1.2.2 Energy Transfers and Transformations
Energy Sources and Characteristics
 Total energy is conserved in a closed
system.
 Chemical & nuclear reactions can be
sources of energy.
 Sun, wind, water, light, and sound can be
energy sources.
 Thermal energy is produced from a
variety of natural sources.
Core Activities
NOTE: When planning your lessons, use the
Planning Guide for explanations and purposes
of the activities in this column.
Additional Internet-based resources may be
found in the teacher materials.
* - Opportunities for Expository or Explanatory
writing
I – Inquiry opportunity
DISCLAIMER: The activities below are one
possible flow. Teachers should feel free to
revise the flow and/or use different activities
that effectively address the same learning
Energy Transfer & Transformation
 Energy can be transferred (from one place targets.
to another).
 Energy can be transformed (from one
The activities below do not necessarily cover all
type into another).
of the concepts that should be addressed during
 When energy is transformed, some is
the year. Individual teachers may decide to
converted into thermal energy or heat.
supplement the provided materials with
 Potential energy is energy stored for
materials of their own.
transformation or use at a later time.
NOTE:
 1 day → 50 min
 Discussion, before and after all
activities, is essential to student
understanding.
2
Questions
Essential Questions (Topical)
1. How would you describe “energy”?
2. If energy is conserved, why is
government and industry always worried
about it?
Knowledge & Skill Questions
1. Describe what happens to the energy in
a gallon of gas when used in a lawn
mower.
2. How can the sun or wind be used as an
energy source?
3. A rock is pulled up with a rope to a
height of 10 m. Describe how this is an
example of energy and how it could be
used.
4. Does all the energy in the Spokane
River water that is used by Avista result
in electrical energy? Explain.
5. Start with the Spokane River. Describe
the transformations that occur as energy
is produced and eventually used by an
appliance in your home.
1. Pre-quiz/Discussion [Note: although the
prequiz is provided in worksheet form, there
are many different ways that the Pre-quiz
and Discussion could be carried out that use
the questions but not the worksheet. For
example, a white-boarding activity.] (1 day)
2. “What Is Energy?” Reading*
(1 day)
3. Energy Transformation Activities*
(1 to 2 days)
4. Conservation of Energy Activity*I
(1 to 2 days)
5. Prime Science Reading (See Expanded Core
Activity Guide for information about some
possible readings.
(2 to 3 days)
6. Baking Soda & Vinegar Rockets*I
(1 to 2 days)
7. Optional: Gadget Project
(2 to 4 days)
8. Video: Bill Nye, Energy
(1 day)
9. Batteries, Bulbs & Buzzers*I
(1 day)
10. Optional: Field trip/guest speaker (1 day)
11. Teacher Designed Formative Assessment
(1 day)
3
Using the systems in the core activities,
6. Explain the forms of energy present in
the system.
7. Compare the potential and/or kinetic
energy in the system at various locations
or times.
8. Explain how energy is transferred within
the system.
9. Describe what happens in terms of
energy conservation to a system’s total
energy as energy is transferred or
transformed.
10. Explain inputs, outputs, transfers, and
transformations of energy in a system.
SUB-SECTION #2: Waves – Sound & Light
(~4 weeks)
Topical Enduring Understanding: There are many types of
waves, yet a common set of properties is used to describe
all waves.
Key Ideas and Enabling Knowledge
Core Activities
GLE References:
1.1.3 Wave Behavior
1.1.4 Forms of Energy
1.2.2 Energy Transfers and Transformations
* - Opportunities for Expository or Explanatory
writing
Nature of Waves
 Types of waves: transverse &
longitudinal (compression)
 Waves move through a medium, but do
not carry the medium
Wave Characteristics
 Frequency, wavelength, speed
 Difference between speed and frequency
 Speed of a wave is determined by the
medium
 Relative speeds of sound and light
 Relationship between frequency and
wavelength
 Wave amplitude as a measure of energy
Wave Interference and Interactions
 Reflection of sound waves
 Waves can add together (constructive
interference) or subtract/cancel
(destructive interference)
 When waves travel from one medium into
another, the speed, wavelength, and
amplitude of the wave may change, but
the frequency does not.
Questions
I – Inquiry opportunity
Sub-Unit 1: Sound & Waves Review
1. Pre-quiz/discussion
(1 day)
2. Prime Science reading*
(1 day)
3. Wave Concepts review
(2 days)
Essential Questions (Topical)
1. How can you describe a wave?
2. What happens if a wave “runs into”
another wave?
3. What happens if a wave “runs into” an
object or other materials?
4. How do mirrors work?
5. What happens when we reach for an
object that is underwater and why?
Knowledge & Skill Questions
4. Wavelength, frequency, & pitch activity*I
(1 day)
5. Extension: Sound levels activity* (1 day)
6. Waveforms activity*
7. Diagnoser/Formative Assessment
(1 day)
4
(1 day)
1. What are the differences between a
transverse wave and a longitudinal
wave? Give and example of each type of
wave.
2. What is the difference between
frequency and pitch?
3. Is a high frequency wave also a high
speed wave? Explain.
4. Draw a longitudinal wave that shows a
loud, low frequency sound.
5. Using the idea of sound intensity, why is
a rock concert seat 20 feet from the
speakers better than a seat 10 feet from
the speakers?
6. Draw a transverse wave that shows a
low energy, high frequency vibration.
Light Waves and Energy
 Energy is required to create a wave
Sub-Unit 2: Waves and Light
 The relationship of visible light & the EM 8. Prime Science reading
spectrum
 Wave speed relationship with respect to
9. Wave speed discussion
the medium, frequency, and wavelength
10. Reflection lab*
Reflection
 Reflection of light and the Law of
11. Mirror application activities*
Reflection: Angle of incidence = Angle of
Reflection
12. Refraction lab*I
Refraction
 Light travels at its “maximum” speed in a
vacuum
 Speed and direction changes as light and
sound waves enter different media
(qualitative Law of Refraction)
 Light waves slow down and bend toward
the perpendicular when entering a more
dense medium
(1 day)
(1 day)
(1 day)
(1 day)
(1 day)
13. Prime Science reading*
(1 day)
14. Sound vs. Light waves
(1 day)
15. Extension: Light & lens activities&
(2 days)
16. Diagnoser/Formative Assessment and/or
companion activity
(1-2 days)
5
7. A transverse wave is moving through a
medium. If the wavelength is increased,
explain what happens to the wave’s
speed.
8. Describe how visible light “fits” into the
overall EM spectrum.
9. What does the amplitude of a wave tell
us about the wave?
10. Explain how the speed of a wave is
related to its frequency and wavelength.
11. If the frequency of a wave passing
through a piece of glass increases,
describe what happens to the speed of
the wave.
12. Explain how a bathroom mirror interacts
with light rays to produce an image.
13. Describe how a magnifying glass can
focus the sun’s rays into a bright spot.
14. In terms of speed and direction, explain
what happens to a light wave as it
travels from glass into water.
15. Compare the properties of sound, light,
and water waves
16. Describe the effects of wave
interference.
17. Explain the forms of energy present in a
system.
18. Describe what happens in terms of
energy conservation as energy is
transferred of transformed.
SUB-SECTION #3: Energy and Electric Circuits
(~1.5 weeks)
Topical Enduring Understanding: Electric current is a way
to transfer energy and accomplish tasks.
Key Ideas and Enabling Knowledge
Core Activities
GLE References: 1.1.4, 1.2.1, 1.2.2, 2.1.3
1.1.4 Forms of Energy
1.2.1 Structure of Systems
1.2.2 Energy Transfers and Transformations
* - Opportunities for Expository or Explanatory
writing
Electric Circuits
 Circuits are energy transformation
devices
 Conservation of energy
 Energy is transformed into heat and light
Questions
How does a battery make a bulb “light up”?
1. Pre-Quiz/Discussion
(1 day)
2. A Battery, A Bulb & A Wire*
(2 days)
3. Conductors & Insulators
(1 day)
4. Extension: The Two bulb circuit* (2 days)
Basic Circuit Characteristics
 Batteries store energy
 Chemical reaction releases energy for
circuit
 Electrons (charges) move through the
circuit
 Current is the rate at which the charges
move
 The charges carry energy through the
circuit
 Complete circuits are required in order to
convert electrical energy into light and
heat
 Some materials conduct current and are
better at transferring electrical energy
Essential Questions (Topical)
5. Extension: Analysis of the Series Circuit /
Analysis of the Parallel Circuit / Resistance
worksheets (1 day if finished as homework)
6. Formative Assessment
(1 day)
7. Summative Assessment
(1 day)
6
Knowledge & Skill Questions
1. You turn on a flashlight; describe the
process (in terms of energy) that
produces light.
2. By describing the energy
transformations, explain how
Conservation of Energy applies to the
flashlight.
3. What is the difference between “charge”
and “current”?
4. If current is the movement or flow of
charges, where do the charges come
from?
5. Does a battery store electrons or energy?
How do you know?
6. Draw a bulb and battery circuit; explain
how it produces heat and light.
7. If a glass fiber was used instead of
copper wire, would the bulb light?
Explain.
8. Describe the battery and bulb circuit as a
system.
9th Grade Physics (Semester 1)
Force and Motion
(8/15/08)
Note: This curriculum was formerly delivered in 10th grade. The Science 9/10 Realignment Team in Spring 2008 reached
consensus that this content will be delivered during the first semester of the 9th grade year.
Overarching Enduring Understandings:
Everything on Earth seems to be moving. We often describe our place in this world in terms where we are compared to objects and other people. As
we move about, our motion is described in terms of where we travel and how fast we go. Understanding motion allows us to predict and plan.
Our motion and the motion of Earth itself is a result of forces. Understanding how these forces affect us and people & objects around us lets us
predict what can happen to their motion.
Using our knowledge of force and motion, we invent machines to make out daily tasks seem easier to accomplish.
Overarching Essential Questions:
 How does the concept of “position” affect your daily life?
 How does the concept of “speed” affect your daily life?
 Where can you see forces affecting your daily life?
 What do machines do to make our tasks easier to accomplish?
Primary State Content Standards Addressed in the Unit – Components & GLE’s
Component 1.1 Properties: Understand how properties are used to identify, describe, and categorize substances, materials, and objects and
how characteristics are used to categorize living things.
1.1.2 Motion of Objects: Understand the positions, relative speeds, and changes in speed of objects.
1.1.4 Forms of Energy: Understand that energy is a property of matter, objects, and systems and comes in many forms (i.e. heat
(thermal) energy, sound energy, light energy, electrical energy, kinetic energy, potential energy, and chemical energy).
Component 1.2 Structures: Understand how components, structures, organizations, and interconnections describe systems.
1.2.1 Structure of Physical Systems: Analyze how systems function, including the inputs, outputs, transfers, transformations, and
feedback of a system and its subsystems.
1.2.2 Energy Transfers and Transformations: Understand how various factors affect energy transfers and that energy can be
transformed from one form of energy to another.
7
Component 1.3 Changes: Understand how interactions within and among systems cause changes in matter and energy.
1.3.1 Nature of Force: Understand factors that affect the strength and direction of forces.
1.3.2 Forces to Explain Motion: Understand how balanced and unbalanced forces can change the motion of objects.
Component 2.1 Investigating Systems: Develop the knowledge and skills necessary to do scientific inquiry.
Component 2.2 Nature of Science: Understand the nature of scientific inquiry.
8
9th Grade Physics Program Guide
Core Unit Outline: Force and Motion
(Unit length: Approximately 44 days)
OPTION: Do Forces before Motion
Sub-Section 1 – Motion
Sub-Unit #1: Position (4 days)
Topical Understanding: The idea of motion
and what affects motion is a framework for our daily
lives.
Key Ideas and Enabling Knowledge
Questions
Core Activities
GLE References:
1.1.2 Motion of Objects
1. Position and Distance
 Position is “Where you are”
 Distance is “How far did you move” (sum of
motion in all directions)
2. Position versus Time Representations
 Position can be shown using graphs, data tables,
or diagrams
 Slope of a position graph can provide motion,
speed, and direction information
NOTE: When planning your lessons,
use the Expanded Core Activity
Guide for explanations and purposes
of the activities in this column.
* - Opportunities for Expository or
Explanatory writing
1. Pre-quiz/discussion*
(1 day)
2. Motion detector activity* (1 day)
3. Minds-On Physics #40* (1 day)
4. Diagnoser/Formative Assessment
(1 day)
9
Essential Questions – Topical
1. How do the ideas of “position” and
“distance” affect your daily life?
2. What information can you get from a
position vs. time graph or data table?
Discussion/Formative Assmt Questions
1. On a position versus time graph, what
does each of the following mean?
A. Positive slope segment
B. Zero slope segment
C. Negative slope segment
2. What does it mean if your position at
t = 0 is 1 km?
3. Does the starting time have to be 0?
Explain and give an example.
4. What does position = 0 mean? Give an
example.
5. You walk 10 miles. Is the distance
traveled the same as your final position?
Sub-Unit #2: Speed/Velocity (11 days)
Topical Understanding: The idea of motion
and what affects motion is a framework for our daily
lives.
Key Ideas and Enabling Knowledge
Questions
Core Activities
GLE References:
1.1.2 Motion of Objects
* - Opportunities for Expository or
Explanatory writing
1. Average Speed
 Average speed of an object: Distance traveled
divided by the amount of time
I – Inquiry opportunity
1. Speed discussion questions and
Pre-quiz/discussion*
(1 day)
NOTE: The GLE only for this sub-unit focuses only on
speed. Students must be able to determine and explain
2. Speed/Time/Distance problems
average speed. Velocity concepts are not a state
(1 day)
requirement.
3. Physics 500 activity*I
(1 day)
2. Average Velocity
 Average velocity of an object: Change in position 4. Speed versus Velocity
(1 day)
divided by the change in time
5. Velocity versus time graph
activity*
(2 days)
3. Speed/Velocity Representations
 The speed of an object at an instant in time can
be determined from speed graphs and data tables 6. Diagnoser/Formative Assessment
 Direction of motion of an object can be
and Speed/Velocity problems
determined from position graphs, data tables and
(2 days)
diagrams or from velocity graphs and data tables
 Average speed/velocity can be determined from
7. Velocity representations* (2 days)
position graphs, pictures, or data tables
8. Formative assessment
(1 day)
10
Essential Questions – Topical
1. How do the ideas of “speed” and
“velocity” affect your daily life?
2. What information can you get from
position and speed graphs or data tables?
Discussion/Formative Assmt Questions
1. What is the difference between average
speed and average velocity?
2. When are average speed and average
velocity the same number?
3. Draw a speed versus time graph that
represents a person driving to a store at a
constant speed, turning around, and driving
home at the same constant speed.
4. For the same situation as in Question #3,
draw a velocity versus time graph.
5. If you look at a speed versus time graph,
how do you find the speed at a certain time?
6. Write a situation where the distance
traveled is the same as the change in
position.
7. When calculating either average speed or
average velocity, does the amount of time
always start at t = 0? Explain and give an
example.
Sub-Unit #3: Acceleration (6-7 days)
Topical Understanding: The idea of motion
and what affects motion is a framework for our daily
lives.
Key Ideas and Enabling Knowledge
Questions
Core Activities
GLE References:
1.1.2 Motion of Objects
* - Opportunities for Expository
or Explanatory writing
NOTE: Calculating average acceleration is not a GLE
evidence of learning. Students must be able to use data
and representations to describe acceleration in a
straight-line situation.
I – Inquiry opportunity
1. Acceleration
2. The Great Race I

Average acceleration of an object moving in a
straight line is the change in speed divided by the
change in time (amount of time for the speed
change)
 If the direction changes during the motion,
average acceleration is the change in velocity
divided the by change in time (amount of time
for the velocity change)
2. Acceleration Representations
 Whether an object is speeding up, slowing down,
or moving at a constant speed can be determined
from graphs, data tables, or diagrams
 Position graphs: Constant slope segments mean
constant speed (no acceleration); curved
segments represent changing speed
 Speed/Velocity graphs: Zero-slope segments
mean constant speed/velocity; non-zero slope
segments represent acceleration
1. Acceleration discussion* (1 day)
(2 days)
3. Diagnoser & Race Track* (1 day)
4. Speed & Acceleration Questions
or Minds-On Physics #250*
(1 day)
5. Formative Assessment: Motion
Questions
(1 day)
11
Essential Questions – Topical
1. How does the idea of “acceleration”
affect your daily life?
2. How do you know if something is
accelerating?
Discussion/Formative Assmt Questions
1. You are riding in a car and the driver
steps on the brake. Is this an example of
acceleration? Explain.
2. A car can travel at a speed of 120 miles
per hour. Describe what you know about the
car’s acceleration.
3. Create a speed versus time data table for
an object that is accelerating (both speeding
up and slowing down).
4. You have an object that accelerates at a
constant rate.
A. Sketch the speed versus time graph
B. Sketch the position versus time graph
5. If you have a constant, positive slope on a
position versus time graph, what would be
the object’s acceleration? Explain.
Sub-Section #2 – Forces
Unit #1: Nature of Forces (7 days)
Topical Understanding: The idea of motion Suband what affects motion is a framework for
our daily lives.
Key Ideas and Enabling Knowledge
Questions
Core Activities
GLE References:
1.1.2 Motion of Objects
1.3.1 Nature of Force
1.3.2 Forces to Explain Motion
1. Forces as Interactions
 Force is always an interaction between two
objects; i.e. forces always occur in pairs
 Two objects will exert equal, but oppositely
directed forces on each other
 Some interaction forces involve objects touching;
others act at a distance: gravity, magnetism, and
electrical force
2. Forces at a Distance
 The strength of the forces at a distance depends
on the mass of the objects (gravity), strength of
the magnets, or the amount of charge (electrical
force)
 As the distance between objects, charged objects,
or magnets increases, the interaction force
decreases
 Two kinds of charge exist: positive and negative.
Another condition, neutral, exists when the
numbers of positive and negative charges are
equal
* - Opportunities for Expository
or Explanatory writing
Essential Question – Topical
Where do you see “forces” affecting your
daily life?
1. Forces and Motion: What Do You
Think?
(1 day)
Discussion/Formative Assmt Questions
1. We say that forces always occur in pairs.
If the earth’s pull on you is one force, what
is the other force in the pair?
2. Which is the greater force: earth’s pull on
you or your pull on the earth? Explain.
3. You have two equal-strength magnets.
You place them 10 cm from each other and
then 100 cm from each other. In which
situation will the force between the two be
the strongest? Explain.
4. Two objects with equal amounts of extra
positive charge are placed 20 cm apart.
Describe the force between them.
5. If the amount of extra positive charge on
each object in Question #4 is doubled,
describe what happens to the force. What
happens to the force if the objects are
moved further apart?
2. Prime Science reading*
(1 day)
3. Inertia demonstrations and
discussion*
(1 day)
4. Force discussion: Book on the
Table
(1 day)
5. Forces as Interactions mini-labs*
(2 days)
6. Diagnoser (as a formative
assessment) and Reading
(1 day)
12
Sub-Unit #2: Balanced and Unbalanced Forces (7 days)
Topical Understanding: The idea of motion
and what affects motion is a framework for our daily
lives.
Key Ideas and Enabling Knowledge
Questions
Core Activities
GLE References:
1.1.2 Motion of Objects
1.3.1 Nature of Force
1.3.2 Forces to Explain Motion
* - Opportunities for Expository
or Explanatory writing
Essential Questions – Topical
How can forces affect your motion?
I – Inquiry opportunity
Discussion/Formative Assmt Questions
1. A 50 N object sits at rest on a table. Are
the vertical forces on the object balanced?
How do you know?
2. A hockey puck is moving at a constant
speed across the ice. What can you tell
about the horizontal forces on the puck?
3. If the friction from the ice in Question 2
is zero, what are the forces on the puck?
4. A car with a mass of 1000 kg is moving
down the road at a constant speed of 20
m/sec.
 What is the net force on the car?
 What are the forces acting on the
car?
 What is the car's acceleration?
5. An unbalanced force of 10 N acts on
a cart with a mass of 1 kg.
1. Forces
 Forces can be described as pushes or pulls
1. Using Forces to Explain Motion
 Forces have size and direction
pre-quiz
(1 day)
 Forces can be added or subtracted to produce a
net force
2. Newton's 2nd Law Lab*I (1 day)
2. Balanced Forces
 Balanced force means that the net force on an
object is zero
3. Balanced forces and the effect on
 An object at rest (zero speed) has balanced forces
motion (lab/demo)*
(1 day)
acting on it
 An object moving at a constant speed still has
4. Prime Science reading and
balanced forces acting on it
questions
(1 day)
3. Unbalanced Forces
 Unbalanced force means the net force is not zero 5. Free-fall activity*I
(2 days)
 Unbalanced forces cause a change in speed or an
acceleration (emphasize gravities effects)
 For a given net force: as mass increases,
6. Diagnoser and Force & Motion
acceleration decreases
questions
(1 day)
 For a given mass: as net force increases,
acceleration increases
 Friction is a force that always opposes the
direction of motion
13
A. If the cart's mass doubles, explain
what happens to the acceleration?
B. If the unbalanced force doubles, what
happens to the acceleration?
Sub-Unit #3: Work (7-8 days)
Topical Understanding: Machines make our daily
work seem easier.
Key Ideas and Enabling Knowledge
Questions
Core Activities
GLE References: 1.1.4, 1.2.1, 1.2.2, 1.3.1
1.1.4 Forms of Energy
1.2.1 Structure of Physical Systems
1.2.2 Energy Transfer and Transformation
1.3.1 Nature of Force
1. Force and Energy
 The total energy in a closed system is conserved
 Work = Force x Distance
 Work is a measure of energy transferred to a
system.
 Some evidences of work are a change in position
or an increase in speed
2. Concept of the Simple Machine
 Simple machines allow us to exert a small force
over a large distance in order to exert a large
force over a small distance.
 Since machines allow us to use a smaller force,
the work seems easier, but the same amount of
work is done (in a frictionless world)
 Because of friction, the work put into the
machine is always greater than the work
produced by the machine.
 Simple machine’s are examples of systems where
Work in = (approximately) Work out
* - Opportunities for Expository
or Explanatory writing
I – Inquiry opportunity
1. Pre-quiz/discussion
(1 day)
2. Prime Science reading and Work
discussion
(1 day)
3. Making the Grade lab*I (1 day)
4. Pulley and Lever activity* (1 day)
5. Machine discussion
(1 day)
6. Work/machine questions and
formative assessment
(1 day)
7. Physics Summative Assessment
(1 day)
14
Essential Questions – Topical
1. How do machines improve society?
2. How do machines really make our work
seem easier?
Discussion/Formative Assmt Questions
1. Many people say: “Machines reduce the
amount of work we have to do”. Explain
why this statement is either true or false.
2. You push and push on a heavy object, but
it does not move. You get really tired; have
you done any work? Explain.
3. You want to use a lever to lift an
extremely heavy object (such as the side of
a small building). Describe what your lever
system would look like.
4. As you push a crate up a ramp, you notice
that the bottom of the crate is getting warm.
Explain where this heat is coming from and
how it affects the amount of force you must
use to move the crate.
5. Explain the relationship between work
and speed.