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Name: _______________________ Date: ________ Period: ______
7th Grade Science
Mr. Vorstadt
Chapter 14 Energy and Power
A book on a shelf ledge has potential energy> It has stored energy that it took to
lift it to the shelf. If the book is bumped and it falls, the potential energy
changes to kinetic energy.
The kinetic energy moves her to the other side of the swing where she slows down
for an instant. She has potential energy at this point and then she swings back.
If she doesn’t use any of her own energy to pump her legs, the swing will eventually
come to a standstill.
Why? _________________________________________________________
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Describe the energy changes that occur for this boom-box radio.
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Kinetic energy is measured in joules. A joule is the energy required to move an
object one meter against the force of one Newton.
1. __________If a hammer has a mass of 2 kilograms and a velocity of 5
meters/second what is the kinetic energy of the hammer?
2. __________What would happen if we double the mass of the hammer but
keep the velocity constant?
3. __________How would things be different if we kept the mass of the
hammer at 2 kilograms but doubled its velocity?
4. __________If a rock has a mass of 20 kilograms is thrown at a velocity of
2 meters/second what is the kinetic energy of the rock?
5. __________What would happen if we doubled the mass of the rock by kept
the velocity constant?
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FORMS OF ENERGY
Energy can never be destroyed: it is just changed from one form to another. When
energy changes from one form to another some heat is given off that is useless to
us, but no energy is destroyed.
Directions: Think of energy changes that take place in your everyday life at home
or school. Describe the energy conversions in the following way:
Toaster
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Electrical energy changed to heat energy and radiant energy
in order to toast the bread.
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Directions: Answer the following multiple choice questions
_____ 1. Energy is the ability to do ________.
a. work
b. power
c. acceleration
d. speed
_____ 2. The fuel used in a rocket is energy stored as __________
a. mechanical energy
b. nuclear energy
c. chemical energy
d. electromagnetic
_____ 3. Energy of motion is ___________
a. kinetic
b. potential
c. chemical
d. solar
_____ 4. A rubber band stretched between two fingers is an example of _______
a. kinetic energy
b. potential energy
c. chemical energy
d. solar energy
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_____5. To a scientist work is only accomplished when ...
a. fuel is burned in an engine.
b. an object is moved by a force.
c. an object is lifted.
d. something makes a sound.
_____ 6. A force is defined as ...
a. fuel for an engine.
c. a push or a pull.
b. an object that is moved a distance.
d. none of these
_____ 7. The energy of motion is called...
a. force
b. friction c. kinetic
d. potential
Directions: Below are a series of images showing Axle the Robot skiing down a hill.
Decide how each image is an example of potential or kinetic energy. From the
multiple choices, decide which is the best description of Axle’s position.
_____ Picture one
a. kinetic energy changing to potential
b. potential energy
c. kinetic energy
d. potential energy changing to kinetic
_____ Picture Two
a. kinetic energy changing to potential
b. potential energy
c. kinetic energy
d. potential energy changing to kinetic
Look at the picture of a roller coaster. Identify the positions labeled with letters
as either examples of points where the roller coaster cars have potential or kinetic
energy.
A. ___________________
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B. ___________________
C. __________________