Chapter 15 - Energy. 15.1 Energy and Its Forms Energy is the ability to do work. Work is the transfer of energy Work = force x distance.
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Chapter 15 - Energy
15.1 Energy and Its Forms Energy is the
ability to do work. Work is the
transfer of energy Work = force x
distance
2 types of Mechanical Energy Kinetic Energy (KE)– Energy of motion
KE = ½ mv2
Potential Energy (PE) – stored energy as a result of position or shape
Gravitational Potential Energy – depends on height
GPE = mgh (mass x 9.8 m/s2 x height) Elastic Potential Energy – PE of an object that
is stretched or compressed
Forms of Energy Mechanical
Energy – associated with the motion and position of everyday objects Sum of KE and PE
Thermal Energy – total KE and PE of all the microscopic particles in an object The greater the thermal energy, the faster the atoms move, the warmer the object is
Chemical Energy – energy stored in chemical bonds Energy released when bonds are broken can do work
Electrical Energy – energy associated with electric charges
Electromagnetic Energy – form of energy that travels through space in the form of waves Ex. Visible light, x-rays, gamma rays
Nuclear energy- energy stored in atomic nuclei Produced by fission and fusion
15.2 Energy Conversion and Conservation
Energy Conversion – changing energy from one form to another
Law of Conservation of energy – states that energy cannot be created or destroyed
15.3 Energy Resources Nonrenewable energy resources
Exist in limited quantities Once used, cannot be replaced
except over millions of years Oil, natural gas, coal, and
uranium are nonrenewable Oil, coal, and natural gas
(fossil fuels)
Renewable Energy Resources Can be replaced in a relatively
short period of time Hydroelectric, solar,
geothermal, wind, and biomass are renewable
Hydroelectric Energy Energy obtained
from flowing water Water flows
downhill converting GPE into KE, water turns turbines that are connected to generators
Solar Energy Sunlight that is
converted into useable energy Passive – use sunlight to heat a building – no machinery
Active – sunlight heats collection plates through which water flows
Geothermal Energy Thermal energy
beneath earth’s surface Can be used to generate electricity in some areas, usually near volcanoes
Biomass Energy
Chemical energy stored in living things. Can be converted directly into thermal energy
Conserving Energy
Reduce needs Increase efficiency
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