Ability to do work or cause change Energy Ability to do work or cause change SI Unit : Joule

- occurs when a force causes an object to move Work – measure of energy that is transferred from one system to another. - occurs when a force causes an object to move

Pg. 115 Interactive

TME = total mechanical energy

Sum of the potential and kinetic energy ME = PE + KE B. Mechanical Energy Sum of the potential and kinetic energy ME = PE + KE

Energy has 2 main types 1) Kinetic Energy 2) Potential Energy

Kinetic energy is the energy of motion. KE = 1/2 mv2 E = energy (Joules) m = mass (kilograms) v = speed (meters/sec.) Marion Jones Sprints t o Victory in the 200 meter.

Kinetic Energy equation KE = ½ mass x velocity2 KE = ½ mv2 Units: kg(m/s)2 or Joule (J)

The kinetic energy of an object depends on its speed and mass. 9

Kinetic and Potential Energy have many forms

Mechanical/Motion Energy - Energy associated with motion

Examples of Mechanical/Motion Energy Person running Car moving Football being thrown

2. Thermal Energy (Heat) - Total energy of the particles in an object

Examples: Fire, oven, hot glue gun

Energy of moving electrons 3. Electrical energy - Energy of moving electrons

Example : electric outlet

4. Radiant or Electromagnetic (Light) energy Energy that travels in transverse waves

Examples: lightbulb, microwave

Travels in longitudinal waves, caused by vibrations 5. Sound energy- Travels in longitudinal waves, caused by vibrations

Example : guitar, boombox

Energy that is stored and held in readiness Potential Energy- Energy that is stored and held in readiness

Potential Energy PE = mgh Potential energy is energy that is stored in an object. PE = mgh h = height g = 9.82 m/s2 * m = mass

Examples of Potential Energy

Potential Energy: Stored energy 4 types Gravational Elastic Chemical Nuclear

A. Gravational P.E. Potential energy due to height Ex. Book on table, airplane Equation: GPE = mass x gravity(9.8) x height

Example of Gravitational PE

b. Elastic Potential Energy energy stored in a stretched or compressed object Ex. Rubberband, spring

Elastic Potential Energy Rank the amount of elastic potential energy of the trampoline from greatest to least. 30

Energy stored in chemical bonds C. Chemical energy - Energy stored in chemical bonds

Examples: wood, food, gasoline, batteries

energy by splitting an atom D. Nuclear energy - energy by splitting an atom

Example : nuclear power , sun, nuclear bomb

Can you find an example of each form of energy in the picture below? 38

C. Energy Transformations – Conversions A change from one form of energy to another

Energy Transformations and Conservation Multiple Transformations A series of energy transformations must occur for you to ride your bike. What are the forms of energy involved in each transformation? 40

D. Law of Conservation of Energy Energy can’t be created or destroyed, it can only be converted.

Law of Conservation of Energy Energy is neither created nor destroyed, but transformed from one form to another. A waterfall has both kinetic and potential energy. The water at the top of the waterfall has stored potential energy. Once the water leaves the top of the fall, the PE is changed into KE.

PSSA Style Question: Using a microscope, a student observes a small, green organelle in a plant cell. Which energy transformation most likely occurs first within the observed organelle? A. ATP to light B. light to chemical C. heat to electrical D. chemical to chemical

Lamp : electrical energy converts to light energy Conversion example 1 Lamp : electrical energy converts to light energy

Water heater : Chemical energy of gas to thermal (heat ) energy Conversion example 2: Water heater : Chemical energy of gas to thermal (heat ) energy

Human body : converts chemical energy in food to motion energy Conversion example 3: Human body : converts chemical energy in food to motion energy

Energy Transformations and Conservation Pendulum A continuous transformation between potential and kinetic energy occurs in a pendulum. What are the types of energy the pendulum has at positions A, B, and C? 52

Energy is Conserved

How does PP&L make electricty for Susquehanna Twp.? Burn coal – make steam – turn turbine – turn generator – make electricity

Energy is conserved

Energy is Conserved

Conversion of Energy When you pick the ball up you give it potential energy.  How high you lift the ball and how much the ball weighs determines how much potential energy it has. When you release the ball, the potential energy is converted into kinetic energy.  The ball continues to have kinetic energy for as long as it stays in motion. 

Energy Transformations and Conservation Conserving Energy While You Ride Transformations between potential and kinetic energy occur during a roller coaster ride. How much potential and kinetic energy does the coaster have at each point? 60