Energy Chapter 13

13.1 What is Energy?  When an object or living thing does work on another object, some of its energy is transferred to that object  Energy is measured in joules  Power is involved whenever energy is being transferred Power = Energy Transferred Time Time  Kinetic Energy -depends on both mass & velocity -changing the velocity of an object will have a greater effect on its kinetic energy than changing its mass. Kinetic Energy = ½ x Mass x Velocity ²

- What Is Energy? Kinetic Energy  Kinetic energy increases as mass and velocity increases.

 Gravitational Potential Energy  GPE is equal to the work done to lift the object  The force you use to lift an object is equal to its weight  The distance you move an object is its height  GPE increases as weight & height increase  Gravitational Potential Energy = Weight x Height

13.2 Forms of Energy  Mechanical Energy  A combination of potential energy & kinetic energy  Sometimes an object’s mechanical energy is its kinetic or potential energy only. Mechanical Energy = Potential Energy + Kinetic Energy  Thermal Energy  All objects are made of particles called atoms & molecules that are constantly in motion  The faster these particles move the more kinetic energy they have

Calculating Mechanical Energy  The kinetic energy of a 500-N diver during a dive from a 10-m platform was measured. These data are shown in the graph. - Forms of Energy

Calculating Mechanical Energy  About 1000 J  According to the graph, how much kinetic energy does the diver have at 8 m?

Calculating Mechanical Energy  Kinetic energy = about 2000 J; potential energy = about 3000 J  Using the graph, find the kinetic energy of the diver at 6 m. Then calculate the diver’s potential energy at that point.

Calculating Mechanical Energy  About 5000 J  The mechanical energy of the diver is the same at every height. What is the mechanical energy of the diver? - Forms of Energy

 Electrical Energy  Depending on whether the charges are moving or stored, electrical energy can be a form of kinetic or potential energy  Chemical Energy  Almost everything is made of chemical compounds  Bonds between atoms and molecules hold chemical compounds together  Nuclear Energy  Released during a nuclear reaction  Electromagnetic Energy  Travels in waves that have some electrical properties and magnetic properties

13.3 Energy Transformations & Conservation  Most forms of energy can be transferred into other forms of energy  One of the most common energy transformations is between potential and kinetic energy  Conservation of Energy  If you add up all the new forms of energy after a transformation, all of the original energy will be accounted for  Matter can be transformed to energy  A small amount of matter releases a huge amount of energy

- Energy Transformations and Conservation  Most forms of energy can be transformed into other forms.

- Energy Transformations and Conservation  A pendulum continuously transforms energy from kinetic to potential energy and back.

13.4 Energy & Fossil Fuels  A fuel is a material that contains stored potential energy  Fossil Fuels contain energy that came from the sun

exists as measured in is the ability to do can be which at a given rate is Graphic Organizer Kinetic energy Energy Potential energy Elastic WorkJoules GravitationalPower