Name: Date: Aim 19: How does energy change from one form to another? Think about some devices you use that you use that converts one form of energy to another…

A. Changes between Kinetic and Potential Energy

 

Energy and Energy Transformations 39

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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 each question. Write the letter of the correct stage on the lines provided. Some stages may be used more than once.

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?

At the ball’s highest point its kinetic energy is zero and its potential energy is maximum.

Kinetic energy is decreasing, and potential energy is increasing.

Kinetic energy isincreasing, and potential energy is decreasing.

Kinetic energy is maximum, and potential energy is minimum.

Kinetic energy is maximum, and potential energy is minimum.

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*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 _______

*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?

Since there is always some _____________________ between surfaces that

____________________ each other, _____________________ and

__________________________________ causes mechanical energy to change to

___________________ (heat) with every movement.

Does the total amount

of energy change?

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 Object 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

Identify the energy transformation occurring in this energy chain

44 Energy and Energy Transformations

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Name Date Class

LESSON 2Lesson Quiz A

Energy TransformationsMultiple 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.

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.

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.

MatchingDirections: 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 heat

10. reduces friction’s creation of thermal energy

A. friction

B. lubricant

C. electric heater

D. cell phone

E. a marble falling off a table

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