Types of Energy
Energy Transformations
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What is Energy
▪ In physics, energy is a property of matter and radiation that can be
transferred to other objects.
▪ Energy is the ability of a physical system to do work.
▪ Energy cannot be created or destroyed, only transformed from one
form to another.
▪ The total amount of energy in a closed system remains constant,
even though it may change from one form to another.
▪ Energy is a fundamental concept in physics.
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Mechanical Energy
▪ Mechanical energy is a type of energy
that is associated with the motion and
position of an object.
▪ It can be divided into two main types:
kinetic energy and potential energy.
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Potential Energy
▪ Potential energy is the energy that an
object possesses due to its position or
state.
▪ The formula is PEg = mgh, where m is
the mass of the object, g is the
acceleration due to gravity, and h is the
height of the object above a reference
level.
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Kinetic Energy
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Thermal Energy
▪ Thermal energy is a type of energy that
is the motion of particles in a substance.
▪ Thermal energy can be transferred in
three ways: conduction, convection, and
radiation.
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Nuclear Energy
▪ Nuclear energy is the energy released through
nuclear reactions, which can be used to generate
electricity.
▪ It also has some significant drawbacks, including
the risk of nuclear accidents and the generation of
nuclear waste, which can remain radioactive for
thousands of years.
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Chemical Energy
▪ Chemical energy is a form of potential energy that is stored in the chemical
compounds.
▪ Chemical reactions can either release energy or absorb energy.
▪ For example, the combustion of gasoline in an engine releases energy in the
form of heat and kinetic energy, which can be used to power a car.
▪ On the photosynthesis in plants absorbs energy from the sun and converts it
into chemical energy, which is stored in the molecules of glucose.
▪ Chemical energy is an important source of energy of the human body, the
operation of machines and engines, and the production of electricity.
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Electromagnetic
Energy
▪ Electromagnetic energy is emitted or transmitted in the form of
electromagnetic waves.
▪ These waves are made up of oscillating electric and magnetic
fields that travel through space at the speed of light.
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Sonic Energy
▪ Sonic energy is a form of energy that is sound waves.
▪ Sound waves are produced by the vibration of objects, which
causes particles in the surrounding medium (such as air or
water) to vibrate and transmit the energy of the sound wave.
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Energy Resources
▪ Energy resources are stores of a
particular type of energy.
▪ Examples of energy resources
include sunlight, wind, waves, coal
and oil.
▪ Coal is an example of an energy
resource of (or store of) chemical
energy.
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Energy
Transformations
The useful energy transfer in an electric lamp that the electric lamp transfers or
converts electrical energy into light energy
Process of using electrical energy
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Energy
▪ Different forms of energy can be
transferred from one form to
another.
▪ The energy transfer diagram below
shows the useful energy transfer in a
car engine. You can see that a car
engine transfers chemical energy,
Process of using chemical energy
which is stored in the fuel,
into kinetic energy in the engine and
wheels.
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Practices
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Exercise
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2. Which of the following states the law of conservation of energy?
A. Potential energy is the energy of position; kinetic energy is the energy
of motion.
B. Energy can be created and destroyed as well as changed in form.
C. Energy cannot be created or destroyed, but can only change in form.
D. Energy cannot be created, destroyed, or changed in form.
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3. During a power outage, George relied upon his flashlight to move around
his home. The flashlight is constructed with wires and a lightbulb enclosed in
a plastic casing. It requires batteries to operate.
Write in the three types of energy involved in turning on and using the
flashlight.
Sound
Nuclear
Chemical
Light
electrical
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4. An oak tree may grow very tall very slowly. It may take the tree a
hundred years to absorb light energy and store it as chemical energy, yet
only a single winter to be turned into heat energy in someone’s wood
stove. Which concept does this fact best relate to?
A. work
B. power
C. force
D. kinetic energy
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5. What does Einstein’s equation E = mc2 express?
A. the relationship between electricity and magnetism
B. the relationship between energy and mass
C. the speed of light in a vacuum
D. the relationship between electrical energy and nuclear energy
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Question 6 refers to the following
diagram.
Which of the following statements is supported by the information in the
diagram?
A. At the high point of its swing, a pendulum has kinetic energy.
B. At the high point of its swing, a pendulum has potential energy.
C. As a pendulum swings through one arc, it loses all its energy.
D. A pendulum can swing forever because of kinetic energy.
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7. According to the kinetic theory of matter, all matter is made up of
molecules in a state of constant motion. The motion of molecules can be
inferred by observing particles in a fluid (a liquid or a gas) as they are hit
by molecules of the fluid. The random, zigzag movement of the particles
is called Brownian motion.
Which of the following is an example of Brownian motion?
A. dust motes dancing in a shaft of sunlight
B. the ground vibrating as a truck passes
C. water evaporating from a puddle
D. an inflatable raft floating on a lake
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