Energy Work and Power
What two things can ME come from?
GPE due to the position of the object or it could be transferred to the object from another source such as being kicked or thrown
What is the formula for potential energy?
PE = m x h x g
What is energy?
The ability to cause change or do work; all changes involve energy
What does gravitational potential energy depend on & what is the formula?
the mass of the object and its height above the earth; GPE = m x h x g
What is thermal energy the total of?
the parties in a material that includes both KE and PE
What does mechanical energy depend on?
the position & motion of an object
What is power and what is the formula? (two definitions & formulas)
the rate at which work is done & the rate at which energy is transferred from one form to another; P = W/t or P = E/t (this works since work and energy are equal since work is the transfer of energy through motion)
What is work?
the transfer of energy through motion; transfer of energy that occurs when a force makes an object move
What is the SI unit of work and what does it equal?
the watt & it equals one joule of work done in one second
When does an object have energy?
when it has the ability to change the environment or itself
When does an object start to have mechanical energy?
when it starts to move
What is fission?
when large nuclei split apart
What is fusion?
when small nuclei combine
What must happen for work to be done?
a force just be applied & an object must move in the direction of the applied force
What is temperature?
a measurement of the average KE of the atoms and molecules in an object
What are nuclear reactions & why does this add mass to the law of conservation of energy?
conversions of small amounts of mass into large amounts of energy; mass is considered to be a potential form of energy and must be conserved when the mass changes into energy
What are the types of potential energy and what are their definitions?
elastic potential energy - energy stored by something that can stretch or compress, chemical potential energy - energy stored in chemical bonds (food, fuel, all chemicals), gravitational potential energy - energy stored in the nucleus of an atom
What is the process of nuclear fission used by in power plants to generate & what are the steps?
electrical energy - nuclear energy from a nuclear reactor releases heat (thermal energy) which changes the water to steam which is used to spin the turbine of an electric generator (sound & mechanical) which is converted to mechanical energy of the magnet or rotors (copper coils) which is converted to electrical energy
What is the law of conservation of energy?
energy can't be created or destroyed - it can be converted into other forms but the total amount never changes
What force is an object accelerated by when it falls?
gravity
What is heat?
internal thermal energy that flows from something with a higher temperature to something with a lower temperature (heat flows from warmer areas to cooler areas)
What does the amount of work done depend on & what is the formula?
it depends on the amount of force exerted and the distance over which the force is applied; W = F x d
What does KE depend on & what is the formula?
it depends on the mass of the moving object & the velocity of the moving object; KE = 1/2 mass x velocity^2
Why is mechanical energy unique & what is the formula?
it is the total amount of potential and kinetic energy in a system or object at any given point in time; ME = KE + PE
What is work and how is it related to energy?
it is the transfer of energy through motion and it is equal to energy because energy is always transferred when work is done so they have the same unit (the Joule)
What are the two main types of energy and what are their definitions?
kinetic energy - energy in the form of motion; potential energy - energy stored in matter