1. Work and Energy Pre-class study material Slide show mode recommended

2. Energy and Work 2 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

3. Types of Energy 3 Mechanical Electrical Electromagnetic Chemical Nuclear Thermal

4. Types of Energy - Mechanical 4 http://www.citruscollege.edu/lc/archive/biology/Pages/Chapter05-Rabitoy.aspx h v Kinetic energy - Energy of a moving object Gravitational protential energy - Energy an object contains due to its position Derivation of energy equation will be discussed in class

5. Types of Energy - Mechanical 5 Elastic potential energy - Energy stored in an object that is being stretched, squashed, twisted, you name it! Kinetic energy - Energy of a moving object Gravitational protential energy - Energy an object contains due to its position Derivation of energy equation will be discussed in class

6. Types of Energy - Mechanical 6 Elastic potential energy - Energy stored in an object that is being stretched, squashed, twisted, you name it! Kinetic energy - Energy of a moving object Gravitational protential energy - Energy an object contains due to its position Sound energy - Associated with the potential and kinetic energy of air molecules What can you hear in vacuum? “Shimmering air”

7. 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 7

8. 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 8 Light energy

9. Types of Energy Chemical energy -Potential of a chemical substance to undergo a transformation through a chemical reaction -Breaking or making of chemical bonds 9 Nuclear energy -Energy released when the nuclei of atoms are split or fused shale rocks containing oil sugar

10. 10 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?

11. 11 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

12. 12 Work and Energy Are you ready for a 3-minute quiz? See you in class!