Energy and Energy Resources Chapter 9 Energy and Energy Resources

Kinetic and Potential Energy 9:1

Terms Energy- the ability to do work Unit: joules (J) Work- involves a transfer of energy and occurs when a force causes an object to move in the direction of the force ( work = force x distance)

Kinetic Energy energy of motion All moving objects have kinetic energy Kinetic energy depends on speed and mass K.E. = m v2 2 K.E. = kinetic energy m = mass v = velocity faster objects — more kinetic energy objects with more mass — more kinetic energy

Try This What is the kinetic energy of a turtle with a mass of .9 kg moving at .05 m/s? 2. What is the kinetic energy of a 6,400 kg tractor trailer traveling at 25m/s?

Potential Energy energy an object has because of its position or shape. Example: stretching a rubber band changes its shape. This gives it elastic potential energy. Gravitational potential energy- energy an object has due to its position above the Earth's surface. Example: lifting up the rubber band gives it G.P.E. Depends on the height and the weight of an object G.P.E. = weight x height

Mechanical Energy the total energy of motion and position of an object. M.E. = P.E. + K.E M.E. = mechanical energy P.E. = potential energy K.E. = kinetic energy Mechanical Energy can be all potential energy, all kinetic energy or part potential and part kinetic energy

Forms of Energy 9:1 continued

Thermal Energy Thermal Energy- total energy of particles that make up an object. Particles at higher temperatures have more thermal energy(because they are moving faster) than the same number and kind of particles at a lower temperature Increasing the number of particles you have in an object increases the thermal energy Mostly kinetic energy Examples: stove, heater, Atlantic Ocean, curling iron, furnaces, etc.

Chemical Energy Chemical Energy- energy of a compound that changes as its atoms are rearranged to form new compounds Much potential energy stored in chemical bonds Potential energy is converted to kinetic energy during the chemical reaction Examples: food, carbohydrates, gasoline, kerosene, butane, firewood, etc.

Electrical Energy Electrical Energy- energy of moving electrons Mostly kinetic energy Examples: TV, VCR, flashlight, computer, calculator, & anything electrical or battery operated

Sound Energy Sound Energy- caused by vibrations of an object Potential energy is converted into kinetic energy Potential energy- example: stretching the string of a guitar Kinetic energy- the string moving and vibrations occurring in the air Examples: speakers, singing, musical instruments, sonar, ultrasounds, taping on a desk, etc.

Light Energy Light Energy- produced by the vibrations of electrically charged particles Mostly kinetic energy Electromagnetic radiation Examples: radio waves, visible light, radar, microwaves, infrared radiation, UV rays, x-rays, gamma rays, etc.

Nuclear Energy Nuclear Energy- the energy associated with the changes in the nucleus of an atom (the nuclei split or join together) Potential energy is converted into kinetic energy Potential Energy stored in the nucleus of an atom Kinetic Energy when the nucleus is split (fission) or joins with other nuclei (fusion) Examples: nuclear fusion in stars and in the sun, nuclear fission at a nuclear power plant, nuclear bombs, some types of radiation therapy, radioactive decay,

Energy Conversions 9:2

Terms Energy Conversion Energy Efficiency Video Segment A change from one form of energy into another Energy Efficiency A comparison with the amount of energy before a conversion with the amount of useful energy after a conversion Video Segment

From Kinetic to Potential and Back

Conversions Involving Chemical Energy