Work and Machines

 P. F52 Potential Energy- Energy that is stored in an object. - - Gravitational Potential Energy- 1) Anytime an object is raised above the ground, it gains more potential energy 2) The greater the object's height and weight, the more GPE it gains. - Formula for calculating an object 's GPE is found by multiplying the object's weight by its height.. ---------------------------------------------------------- P. F 53 Kinetic Energy - Energy an object has due to its motion. KE of a moving object depends on both its speed and mass....the greater the mass or the higher the speed, the greater the KE. - Kinetic Energy is sometimes changed into other forms of energy: Example 1: friction between a roller coaster's wheels and track changes some KE into heat energy. Example 2- Kinetic Energy of our bodies moving about results in electrical energy for our nerves to carry signals, or thermal energy for our bodies to keep warm. ---------------------------------------------------------- P. F 54 - Forms of Energy: Energy can take many forms. - COPY THE TABLE IN THE TOP RIGHT CORNER OF PAGE F 54 IN YOUR NOTES WORD FOR WORD. - Examples: 1) A fuel cell converts chemical energy into electricity. 2) The vibrations of a stereo speaker are a source of sound energy. --------------------------------------------------------- P. F 55 -Batteries change chemical energy into electricity - -When a secondary battery is recharged , an outside source of electricity forces electrons through the battery. --------------------------------------------------------- P. F 56 - Work is applying force on an object to move it through a distance. - -When work is done on an object, energy is added to it. - -Joule - a measure of work - -Formula: Multiply distance by the force ------------------------------------------------------------ P. F 57 How work turns into heat: Example: As a book is pushed into across a desktop, the friction between a book and the desktop turns energy into heat energy. - The amount of heat energy produced is equal to the work done. ------------------------------------------------------------- P. F 58 - Work is equal to the force multiplied by the distance the object moves. - -The force needed to lift an object is equal to the weight of the object. ------------------------------------------------------------ P. F 60 Can Energy Be Created or Destroyed? The amount of energy in the universe remains constant. Energy is not created or destroyed. Energy may be changed from one form of energy to another form. These principles are known as the "Law of Conservation of Energy."