Energy Chapter 5 Section “M”

Energy Energy: is the ability to do work. Energy: is the ability to do work. Two types of energy Two types of energy Kinetic energy Kinetic energy Potential energy. Potential energy. The energy an object has due to its motion is kinetic energy. The energy an object has due to its motion is kinetic energy. Factors that effect kinetic energy depend on mass and velocity. Factors that effect kinetic energy depend on mass and velocity. Calculating: kinetic energy=1/2 x mass x velocity2 Calculating: kinetic energy=1/2 x mass x velocity2 Potential energy: stored energy that results from the position or shape of an object. Potential energy: stored energy that results from the position or shape of an object.

Energy continued Gravitational potential energy Gravitational potential energy Gravitational potential energy: Potential energy related to an objects height Gravitational potential energy: Potential energy related to an objects height G.P.E= weight x height G.P.E= weight x height Elastic potential energy: The potential energy associated with objects that can be stretched or compressed. Elastic potential energy: The potential energy associated with objects that can be stretched or compressed.

Forms of energy Mechanical energy Mechanical energy Thermal energy Thermal energy Electrical energy Electrical energy Chemical energy Chemical energy Nuclear energy Nuclear energy Electromagnetic energy Electromagnetic energy

Mechanical energy Mechanical energy: Energy associated with the position and motion of an object. Mechanical energy: Energy associated with the position and motion of an object. Examples: Examples: Car driving Car driving Football being thrown Football being thrown Writing these notes Writing these notes Mechanical energy = potential energy + kinetic energy. Mechanical energy = potential energy + kinetic energy.

Thermal energy Thermal energy: the total potential and kinetic energy of the particles in an object. Thermal energy: the total potential and kinetic energy of the particles in an object.

Electrical energy Electrical energy: the energy of an electrical charge Electrical energy: the energy of an electrical charge Two types of electrical energy Two types of electrical energy Kinetic Kinetic Potential Potential Examples Examples Lightning Lightning Power in power lines Power in power lines

Chemical energy Chemical energy: Is potential energy stored in the chemical bonds that hold chemical compounds together. Chemical energy: Is potential energy stored in the chemical bonds that hold chemical compounds together. Almost everything you touch has chemical energy. Almost everything you touch has chemical energy. Examples Examples Food Food Photosynthesis Photosynthesis

Nuclear energy Nuclear energy: is energy stored in the nucleus of an atom. Nuclear energy: is energy stored in the nucleus of an atom. There are two types of nuclear reaction. There are two types of nuclear reaction. Nuclear fission Nuclear fission This is what happen when a nucleus of an atom splits. This is what happen when a nucleus of an atom splits. Examples : Nuclear power plant Examples : Nuclear power plant Nuclear fusion Nuclear fusion This is what happens when the nuclei of atoms fuse or join together. This is what happens when the nuclei of atoms fuse or join together. Examples: Sun. Examples: Sun.

Electromagnetic Energy Electromagnetic energy: travels in waves which have some electrical properties. Electromagnetic energy: travels in waves which have some electrical properties. The energy we receive from the sun The energy we receive from the sun X-rays X-rays Microwaves Microwaves Ultraviolet and Inferred light Ultraviolet and Inferred light Radio waves Radio waves

Energy transformation and conservation Energy transformation: forms of energy that can be transformed into other forms of energy.

Single transformation Single transformation: When energy is transformed from one type of energy to another to get work done. Single transformation: When energy is transformed from one type of energy to another to get work done. Examples: Examples: Chemical energy x to mechanical energy Chemical energy x to mechanical energy Electrical energy x to thermal energy Electrical energy x to thermal energy

Multiple transformation Multiple transformation: a series of energy transformations is needed to do work. Multiple transformation: a series of energy transformations is needed to do work. Examples: Examples: Lighting a match: Wright down all of the types of energy needed or are a result of lighting a match starting with the act of strike the match. Lighting a match: Wright down all of the types of energy needed or are a result of lighting a match starting with the act of strike the match. Mechanical, to strike the match then thermal, this releases stored chemical energy which gives off thermal energy and last electromagnetic in the form of light. Mechanical, to strike the match then thermal, this releases stored chemical energy which gives off thermal energy and last electromagnetic in the form of light.

Transformation between potential and kinetic energy Energy transformation in throwing a baseball up in the air. Energy transformation in throwing a baseball up in the air. Energy transformation in a pendulum Energy transformation in a pendulum Energy transformation in a pole vault Energy transformation in a pole vault

Potential to kinetic One of the most common energy transformations is the transformation between potential energy and kinetic. One of the most common energy transformations is the transformation between potential energy and kinetic.

Base ball being throw up in the air Lets disscuss what happens when you throw a baseball. Lets disscuss what happens when you throw a baseball. Write the different conversions of energy down. Write the different conversions of energy down.

Conservation of energy Law of conservation of energy Law of conservation of energy As with the law of conservation of mass, the law of conservation of energy states: Any energy at the beginning of the “work” will be accounted for at the end. Energy cannot be created or destroyed. As with the law of conservation of mass, the law of conservation of energy states: Any energy at the beginning of the “work” will be accounted for at the end. Energy cannot be created or destroyed. Examples: a quarter spinning. Examples: a quarter spinning.

Energy and friction Friction effects how energy is transferred to all moving objects. Friction effects how energy is transferred to all moving objects. This transforms mechanical energy to thermal energy. This transforms mechanical energy to thermal energy.

Energy and Fossil fuels Formation of fossil fuels Formation of fossil fuels Millions of years ago plants grew in huge forests. The energy they absorbed from the sun is trapped in these decaying plant material. Millions of years ago plants grew in huge forests. The energy they absorbed from the sun is trapped in these decaying plant material. Energy from the sun. Energy from the sun. Light converted into chemical (plants) Light converted into chemical (plants) Stored as potential chemical energy Stored as potential chemical energy Now the chemical is converted into thermal as we burn it in our cars and homes. Now the chemical is converted into thermal as we burn it in our cars and homes.

Use of fossil fuels They are burned to change chemical energy to thermal energy. They are burned to change chemical energy to thermal energy. Combustion: the process of burning fuels. Combustion: the process of burning fuels. Power plants (coal) Power plants (coal) Homes (natural or propane gas) Homes (natural or propane gas) Cars, trains, and planes (petroleum/gasoline) Cars, trains, and planes (petroleum/gasoline)