Unit 4: Alternative Energy Topic 1:Energy Power & Energy 3201
The relationship between work and energy Understanding the relationship between work and energy forms the basis of how energy is converted and transferred and is important within the study of alternative energy concepts.
Force push or a pull on an object. due to Gravity magnetism or anything that might cause a mass to accelerate.
Work object moves the work has been done. Work is defined as the force exerted on an object multiplied by the distance the object travels while the force is exerted. three key ingredients to work – force, displacement, and cause. In order for a force to qualify as having done work on an object, there must be displacement and the force must cause the displacement.
Energy defined as the ability to do work. It doesn’t mean that the object will actually move but that it can. This is the only difference between work and energy; they even have the same units of measurement – Joules.
Kinetic Energy Kinetic energy is the energy of motion. A speeding car has a significant amount of energy it can transfer to something, while a parked car does not. When the kinetic energy of an object changes, work has been done on the object.
Potential Energy Potential Energy is the energy of position, or the energy something gets from either its own physical properties, or its distance from the surface of the earth. Potential energy is stored energy or stored work.
Work = Change in Energy We exert a force on something to raise it above the ground, and how far we raise it would be the distance we exert that force. The work done to raise that object would then be equal to the potential energy it has gained. For kinetic energy the force required to stop the motion over the distance it is exerted is the same as the kinetic energy the object has. This would be the work done to stop the object and would be equal to the kinetic energy.
Gravitational Potential Energy The water above receives energy as it falls down the short waterfall. The water gained kinetic energy as it drops. A molecule of water is going faster when it hits the bottom of the waterfall than it was when it went over the top of the waterfall.
Main Types of Energy Radiant Energy Stored Mechanical Energy Nuclear Energy Motion Sound Gravitational Energy Thermal Energy Electrical Energy Chemical Energy
First Law of Thermodynamics Energy can be transferred/converted but cannot be created or destroyed. A fossil fuel burning in an engine converts its stored chemical energy to mechanical energy through combustion (a chemical process). Some of the energy is converted and lost from the engine to heat, friction, sound and light.
Energy does not just appear, it has to have some source…whether it can be seen or not. From an alternative energy perspective the major energy sources, wind, water and solar all come as a conversion from something else. Wind and water and direct conversions from mechanical energy, while solar is also partially such a conversion as well as an electro-chemical one.
Assignment Complete the assignment called The Types of Energy.