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Work and Energy. Pre-class study material Slide show mode recommended. Energy and Work. Energy: the ability to do work – money in bank accounts Work: energy transferred to or from an object by means of a force acting on the object – money transferred between accounts. Types of Energy.
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Work and Energy Pre-class study material Slide show mode recommended
Energy and Work • Energy: the ability to do work – money in bank accounts • Work: energy transferred to or from an object by means of a force acting on the object – money transferred between accounts
Types of Energy • Mechanical • Electrical • Electromagnetic • Chemical • Nuclear • Thermal
Types of Energy - Mechanical Kinetic energy - Energy of a moving object v Gravitational protential energy - Energy an object contains due to its position h Derivation of energy equation will be discussed in class http://www.citruscollege.edu/lc/archive/biology/Pages/Chapter05-Rabitoy.aspx
Types of Energy - Mechanical Kinetic energy - Energy of a moving object Elastic potential energy - Energy stored in an object that is being stretched, squashed, twisted, you name it! Gravitational protential energy - Energy an object contains due to its position Derivation of energy equation will be discussed in class
Types of Energy - Mechanical Kinetic energy - Energy of a moving object Elastic potential energy - Energy stored in an object that is being stretched, squashed, twisted, you name it! Gravitational protential energy - Energy an object contains due to its position Sound energy - Associated with the potential and kinetic energy of air molecules “Shimmering air” What can you hear in vacuum?
Types of Energy Electrical energy • Supplied by the combination of electric current and electrical potential that is delivered by the circuit • Caused by movement of electrons
Types of Energy Electromagnetic energy • Energy emitted and absorbed by charged particles which exhibits wave-like behavior as they travel through space • Radio bands • Microwave • Infrared • Visible light • Ultraviolet • X-rays • Gamma rays Light energy
Types of Energy Chemical energy • Potential of a chemical substance to undergo a transformation through a chemical reaction • Breaking or making of chemical bonds shale rocks containing oil sugar Nuclear energy • Energy released when the nuclei of atoms are split or fused
Types of Energy Thermal energy • Energy of a substance or system related to its temperature, i.e., the energy of moving or vibrating molecules What’s the relationship between thermal energy and heat?
Work and Energy Conversion • Doing work = Transferring energy • The transfer of energy sometimes accompanies the conversion between different types of energy • I lift a heavy box: I apply force to increase the gravitational potential energy of the box • The tungsten bulb lights up: electrical energy heats up the filament, i.e. increase thermal energy, which converts to electromagnetic energy (light) • Name some work and energy conversion you see in daily life • Relationship between thermal energy and heat: heat is the energy transferred from one body to another by thermal interactions
Work and Energy Are you ready for a 3-minute quiz? See you in class!