Download How does energy change from one form to another?

Name:
Aim 19: How does energy change from one form to another?
Date:
Think about some devices you use that you use that converts one form of energy to another…
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Date
Class
Key Concept Builder
LESSON 2
Energy Transformations
Key Concept What is the law of conservation of energy?
Directions: In the diagram, a ball has just been thrown and is about to be caught. Use the diagram to answer
A. Changes
between Kinetic and Potential Energy
each question. Write the letter of the correct stage on the lines provided. Some stages may be used more than once.
At the ball’s highest point its
kinetic energy is zero and its
potential energy is maximum.
KEPE
C.
Total
energy
Kinetic energy is
decreasing, and potential
energy is increasing.
KEPE
D.
Total
energy
Kinetic energy is
increasing, and potential
energy is decreasing.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
B.
KEPE
Kinetic energy is
maximum, and potential
energy is minimum.
A.
KEPE
Total
energy
Total
energy
E.
Kinetic energy is
maximum, and
potential energy
is minimum.
KEPE
Total
energy
1. At which stages is kinetic energy at the maximum value?
and
2. At which stage is the kinetic energy zero?
3. Which stage has increasing kinetic energy and decreasing potential energy?
4. At which stage is the potential energy at the maximum value?
5. At which stages is potential energy at its minimum?
and
6. Which stage has decreasing kinetic energy and increasing potential energy?
Energy and Energy Transformations
39
*When you throw a ball upward, the ball has its GREATEST SPEED and therefore the MOST ________.
*At the ball’s HIGHEST POINT, the ball has the MOST _______
C355_038_041_CRF_L2KeyCo_892496.39 39
1/6/10 9:07:18 PM
*As the ball MOVES BACK DOWNWARD, ______ decreases and _______ increases B. The Law of Conservation of Energy
What is the Law of
Conservation of
Energy?
Energy can be ______________________ from one form into another or
______________________ from one region to another, but the energy cannot be
__________________ or __________________
If energy is conserved,
how come when you
stop pedaling your
bicycle, you will
eventually come to a
stop?
Does the total amount
of energy change?
Since there is always some _____________________ between surfaces that
____________________ each other, _____________________ and
__________________________________ causes mechanical energy to change to
___________________ (heat) with every movement.
The _________________________________ (total energy) stays _________________.
Think about the energy transformation that occurs when you ride your bike…
1. You first need energy to get yourself to start riding a bike. •
Where does this come from? _________________
•
What type of energy is this?__________________
2. Once you have ____________________ energy, this allows your leg and foot muscles to pump the pedals of
the bicycle.
•
What is this type of energy called? _________________
3. The pedals were first not moving, and therefore were storing _____________________ energy.
•
What does this type of energy transform into when you push down the pedal? _____________________
4. All of the parts of the bicycle are not moving thanks to ____________________ energy.
•
Since you are encountering friction during your bike ride, energy is being lost as _________________
•
What type of energy is this? __________________
•
Does the total amount of energy ever change? _____________
C. What are some forms of Energy Transformations?
Determine which picture matches the energy transformations listed below. Energy Transformation
Chemical energy à radiant energy
Electrical energy à mechanical energy
Chemical energy à radiant energy and thermal energy
Mechanical energy à sound energy
Electrical energy à sound energy
Gravitational potential energy à kinetic energy and sound energy
Electrical energy à sound energy and radiant energy
Chemical energy à mechanical energy and thermal energy
Object
Identify the energy transformation occurring in this energy chain
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Class
Lesson Quiz A
LESSON 2
Energy Transformations
Multiple Choice
Directions: On the line before each question or statement, write the letter of the correct answer.
1. An energy
occurs when energy changes from one type to another type.
A. increase
B. conversion
C. transformation
2. What happens to potential energy when a ball is tossed into the air?
A. It never changes.
B. It increases as the ball approaches its highest point.
C. It decreases as the ball approaches its highest point.
3. According to the law of conservation of energy, energy cannot
A. be created or destroyed.
B. transferred from one region to another.
C. transformed from one form into another.
5. What type of energy transformation occurs during photosynthesis?
A. Radiant energy becomes chemical energy.
B. Thermal energy becomes chemical energy.
C. Nuclear energy becomes mechanical energy.
Matching
Directions: On the line before each definition, write the letter of the term that matches it correctly. Each term is
used only once.
6. transforms gravitational potential energy into
kinetic energy
7. transforms mechanical energy into thermal
energy
8. transforms radiant energy into sound energy
9. force that reduces kinetic energy and produces
A. friction
B. lubricant
C. electric heater
D. cell phone
E. a marble falling off a
table
heat
10. reduces friction’s creation of thermal energy
44
Energy and Energy Transformations
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
4. When a ball is thrown into the air, its kinetic energy is lowest
A. at its highest point.
B. at the moment it is released.
C. as it begins to fall back to the ground.