Download KE = ½ m v2

Name: _____________________________ Date: _______________ Hr: ________
Kinetic Energy
1.
ENERGY HOMEWORK PACKET
The story so far …
Stationary things ________________________________.
It takes a __________________________.
Force equals __________________________________ and is measured in __________________.
When a force moves something through a __________________________________.
Work is measured in __________________.
One joule is the amount of work done when _______________________________________ of one meter.
2. Why is the lazy pool ball force to move?
3.
Why is one ball able to move the other ball?
4.
When you have both mass and speed you have what?
5. What is energon? Where does it come from?
6.
What does it mean?
7. How did the Q-ball get its energy?
8. What two things are measured in joules?
9. Who uses joules of energy?
10. What is the Greek word for movement?
11. What is kinetic energy?
Potential Energy
12. The story so far…
Things that are moving have the ____________________________ and to apply a force through a
_________________________.
They can be said to ____________________________________.
Another word for “work in” is _____________________.
Since energy is simply the ability to do work, and since work is ________________________, energy is
________________________________.
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The energy of movement is called __________________________________.
13. Why is the giant knocked out by the stone?
14. Give an example of air and water having energy.
15. Why should the guy in the cartoon not be standing under the rock if it
doesn’t have kinetic energy at the moment?
16. Does the rock have energy if it is not moving? What is it called?
17. What is potential energy?
18. What happened to the stone when its thrown this time?
19. Explain how the kinetic energy is transferred to potential energy and then back to kinetic energy.
20. How does the giant convert potential energy to kinetic?
KE = ½ m v2
w = weight in N (can be found by mass in kg x 9.8 m/s2)
PE
w
h
Part 1: Potential and Kinetic Energy Calculations
1.
What is the kinetic energy of a 1000 kg rollercoaster moving at a speed of 20 m/s?
2. If the rollercoaster above was moving twice as fast, what is the new KE?
3. If the rollercoaster in number 1 had double the mass and the same speed, what would the kinetic energy be?
4. Missy Diwater, the former platform diver for the Ringling Bros Circus, had a kinetic energy of 15,000 J just
before she hit the water. If her mass is 50 kg, what is her speed?
5. A 750 kg compact car travels at 100 m/s and has 3,750,000 J of kinetic energy. What is the KE of the car if
it travels at 50 m/s?
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6. John has a 50 kg object suspended in air, 50 m above the ground. If the object is dropped, how much
work will be done?
7. Mrs. Jacobs dropped an object from a height of 10 m. What was the weight of the object if it did 50 J of
work?
8. A cart is loaded with a brick and pulled at a constant speed along an inclined plane to the height of a seat
top. If the mass of the brick and cart is 3.0 kg and the seat is 0.45 m high, what is the potential energy of
the brick and cart when they reach the top?
Part 2: More Kinetic and Potential Energy Calculations
1. A moving car has kinetic energy. If it speeds up until it is going 4 times the original speed, how much kinetic
energy does it have compared to the original?
2. When the mass of a moving object is doubled with no change in speed, by how much will the kinetic energy
change?
3. When the velocity of an object is doubled, by what factor is its kinetic energy changed?
4. Car A is lifted a certain distance in a service station and therefore has potential energy relative to the floor.
If car B were lifted twice as high, how much potential energy would Car B have compared to Car A?
5. Two cars are lifted to the same height in a service station. If car A is twice as massive as the Car B, which has
more potential energy? How much more? Why?
6. How many joules of potential energy does a 1 N book gain when it is elevated 4 m? 8 m?
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Part 3: Conservation of Energy
A bull drops a rock off the edge of a cliff. The rock is 2 kg and the
cliff is 125 m tall.
1. What is the potential energy of the rock before it begins to fall?
2. What is the kinetic energy before it begins to fall?
3. 3 seconds after the rock is dropped, what is its new height off the ground below? Hint: Use this formula for
distance d = 4.9 (t) ²
4. So what is its new P.E.?
5. And how much P.E. has it “lost” since starting to fall?
6. What is the new velocity of the rock 3 seconds after it got dropped?
7. So what is its new kinetic energy?
8. And how much KE has it gained?
9. Now compare the amount of PE lost and KE gained. Explain
10. Now do the same calculations (3 through 9) but consider the rock 5 seconds after it was dropped.
3.
4.
5.
6.
7.
8.
9.
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UNITED STREAMING: Energy: Work and Power - Video
Pre-Test
Directions: This will help you discover what you know about the subject of energy before you begin this lesson. Answer the
following true or false.
1. To a physicist, energy is work or the capacity to perform work.
T_______ F_______.
2. An example of kinetic energy is water sitting above a dam.
T_______ F_______.
3. Atoms do not have energy.
T_______ F_______.
4. A book sitting on a bookcase has potential energy.
T_______ F_______.
5. Matter could not exist without electrical energy.
T_______ F_______.
6. Energy from the sun comes to Earth in the form of heat.
T_______ F_______.
7. Fusion is the process of atoms splitting apart.
T_______ F_______.
8. Sound is a form of energy.
T_______ F_______.
9. Energy is being constantly recycled from one form to another.
T_______ F_______.
10. The three laws of thermodynamics are a measure of light, heat, and sound. T____F____.
Vocabulary Definitions
The following words and terms used in the program may be unfamiliar to you. Try to listen for these terms while viewing
the program, pay close attention so you can later include them in your scientific descriptions, observations, and creative
writing assignment activities.
Use the Right Word
Directions: Find the right word from the physics vocabulary list that completes the following sentences.
1. The form of energy that results in movement of any object is called ____________.
2. The energy of position, or energy prior to movement, is called ____________ energy.
3. Radiant energy from the sun is a form of ____________ energy.
4. Under intense heat, like in the core of the sun, two hydrogen atoms will fuse releasing energy. This is called
____________.
5. When the nucleus of an atom is split apart energy is released. This process is called ___________.
6. The source of energy of all living things is in a process called ____________.
7. Energy is constantly being changed and recycled into different forms. This is called energy ____________.
8. The first law of thermodynamics states that energy cannot be created or destroyed. This is sometimes called the law of
the ____________ of energy.
9. If a machine is stopped it will adjust to a single uniform temperature until it reaches ____________ with the other objects
that surround it.
10. Einstein's famous formula that links energy and matter is ____________.
Word Match
Directions: Connect the word with the proper definition.
energy
energy always flows from hot to cold
energy conservation
cannot be created of destroyed
energy exchange
when hydrogen atoms fuse
fusion
a form of electromagnetic energy
kinetic energy
energy of position
light
when energy changes from one form to another
nuclear energy
work or the capacity to do work
potential energy
formula for the expenditure of work or energy
second law
energy of movement
W = Fx
energy in the nucleus of atoms
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Vocabulary
absolute zero - at this temperature matter is devoid of energy. Absolute zero is -273 degrees Celsius, or -460 degrees
Fahrenheit.
atom - the smallest unit of matter, made up of a nucleus of protons and neutrons and orbiting electrons.
chemical energy - a form of energy locked in the cells of living or fossilized plants and animals.
E = mc² - Albert Einstein's famous equation, is read: Energy (E), equals (=) mass (m), times the speed of light, squared (c²).
Einstein, Albert - German-American physicist,
1879 - 1955.
electromagnetic energy - waves of electricity and magnetism, called electromagnetism. It is often called light.
electron - negatively charged particles that orbit the nucleus of atoms.
energy - in physics, work or the capacity for doing work.
energy exchanges - process where energy changes or is recycled from one form to another.
first law of thermodynamics - energy cannot be created or destroyed.
fission - when the nucleus of atoms are split apart releasing energy.
fusion - when two hydrogen atoms fuse under extreme heat, energy is released. Fusion is the energy of the sun and stars.
heat - a form of kinetic energy. Heat is sometimes called thermal energy.
kinetic energy - form of energy that results in the movement of an object.
law of conservation of energy - theory that energy cannot be created or destroyed. This is the first law of thermodynamics.
mass - total quantity of an object's matter.
matter - the material that make up objects. Matter cannot be created or destroyed.
matter-energy connection - theory that matter and energy are fundamentally the same.
molecules - compounds made up of two or more atoms.
nuclear energy - the energy locked in the nucleus of atoms.
photosynthesis - the process carried out by green plants and some microorganisms in which carbon dioxide, water, and
sunlight are converted into ATP and glucose, releasing oxygen as a by-product.
potential energy - energy that has the potential for doing work.
second law of thermodynamics - the temperature of all things flow in one direction, towards equilibrium.
sound - a form of kinetic energy.
third law of thermodynamics - at absolute zero matter is devoid of energy.
work - in physics, is when a force is applied to an object so that it moves a distance.
Connected/Not Connected
Directions: Place the following words in the proper sentences.
absolute zero
atoms
Albert Einstein
Chemical
E = mc²
electromagnetic
energy
exchanges
fission
fossil
fusion
kinetic
molecules
nuclear
potential
recycling
solar
sun
W = Fx
WORK
1. ____________ is connected to ____________ because it is a formula for the expression of energy.
2. ____________ energy is NOT connected to ____________ energy because one is the energy of movement and the other is
the energy of position.
3. ____________ are connected to ____________ because both are forms of matter.
4. ____________ is NOT connected to ____________ because one is the process by which hydrogen atoms fuse, releasing
energy, and the other is the process where the nucleus of atoms are blown apart, releasing energy.
5. The ____________ is connected to ____________ energy because the major source of this form of energy for the earth
comes from this heavenly body.
6. ____________ energy is NOT connected to ____________ energy because one is energy formed through the
photosynthesis process and the other is energy in the nucleus of atoms.
7. Energy ____________ are connected to the ____________ of energy because energy has the ability to be transformed
from one form to another.
8. ____________ energy is NOT connected to energy gained from the burning of ____________ fuels because one form of
energy causes no air pollution and the other produces greenhouses gases harmful to the environment.
9. ____________ is connected to ____________ because he formulated this famous formula.
10. ____________ is NOT connected to ____________ because when a substance reaches this point the electrons have
almost no movement.
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Video Quiz
Directions: Answer the following true or false, or fill in the blank with the correct word to make it true.
1. Energy can be created and sometimes destroyed. T_______ F_______.
2. The formula physicists use to express the expenditure of work or energy is ______________.
3. Kinetic energy is described as energy of matter in motion.
T_______ F_______.
4. Potential energy is not important in the total amount of energy available in the universe.
T_______ F_______.
5. Electromagnetic energy only exists as radiant energy from the sun and stars. T_______ F_______.
6. Under intense heat two hydrogen atoms will fuse to form a helium atom and release energy. This process is called
____________.
7. Photosynthesis is a process that converts energy from the sun into chemical energy in the leaves of plants. T_______
F_______.
8. Energy can be changed and recycled from one form to another. T_______ F_______.
9. The second law of thermodynamics concludes that all things are moving towards ____________.
10. Einstein's formula of E = mc² states that energy equals mass times the speed of light squared. T_______ F_______.
Post-Test
Vocabulary
Directions: Fill in the blank with the appropriate
absolute zero
equilibrium
atom
exchange
chemical
fission
electromagnetic
fusion
electron
force
term from the list below.
heat
solar
kinetic
sound
molecules
thermodynamics
nuclear
wind
potential
work
1. Sound and heat are examples of ____________ energy.
2. The water stored above a dam and the energy locked in the nucleus of an atom are both examples of ____________
energy.
3. When cows convert the energy in grass into energy that can be used in their bodies that is an example of an energy
____________.
4. Physicists have summarized their understanding of heat and energy into the three laws of ____________.
True or False
Directions: Fill in the blank with True or False. If the statement is false, change it to make the statement true. Rewrite the
true statement in the space provided.
5. ________ To a physicist, work and energy are two separate and distinct concepts.
6. ________ Sound is a form of nuclear energy.
7. ________ A tree standing in a forest has potential energy.
8. ________ Electromagnetic energy from the sun cannot be changed into chemical energy.
9. ________ Energy from the wind creates pollution because greenhouse gases are released in the process.
Essay Section
Directions: Answer the following questions in complete sentences. Use the back of this page or a separate sheet of paper if
you need more space to complete your answer.
10. Why is heat a form of kinetic energy?
11. Explain why energy from wind is less polluting than the energy from fossil fuel.
12. Explain energy exchanges and give some examples.
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