Download Energy is the ability to do work or to produce change

Chapter 13 Notes
Energy is the ability to do work or to produce change.
Energy is transferred from one object to another when work is done.
Work is the transfer of energy.
Kinetic energy is the energy that an object has because of its motion.
Kinetic energy depends on both the object’s mass and velocity.
Kinetic energy increases as mass increases.
Kinetic energy = (Mass x Velocity2) / 2
Potential energy is the energy that an object has because of its position or condition.
Potential energy is energy that is stored and held in readiness.
Six forms of energy are:
1. Mechanical – the energy associated with the motion or position of an object
can occur as kinetic or potential energy
2. Thermal –
total energy of the particles in a substance or material
particles can have both potential and kinetic energy due to their arrangement or
motion
3. Chemical – potential energy stored in chemical bonds that hold chemical compounds
together
4. Electrical energy carried by moving electric charges that produce electricity
5. Electromagnetic –
energy that travels in waves such as visible light, ultraviolet radiation,
microwaves, and infrared radiation
6. Nuclear –
potential energy stored in the nucleus of an atom and released during nuclear
reactions. There are 2 Types of nuclear reactions: nuclear fission (nucleus splits)
and nuclear fusion (nuclei fuse or join together)
Elastic potential energy is the potential energy associated with objects that can be stretched or
compressed. (ex: archer pulling a bow)
Gravitational potential energy is potential energy that depends on height. (ex: lifting an object)
Gravitational potential energy = weight x height (Newton-meters or Joules)
Gravitational potential energy (J) = Mass (kg) x gravitational acceleration (9.8 m/s 2)x height
An energy conversion or transformation occurs when energy changes from one form to another.
Most forms of energy can be converted into any other form.
Example: Your body converts the chemical energy in the food you eat to the mechanical energy you need
to move your muscles and to thermal energy you need to maintain body temperature.
The law of conservation of energy states that in any process, no energy is lost.
Energy cannot be created or destroyed according to this law.
Einstein’s theory of relativity included a small change to this law – it is possible for matter to be converted
to energy – BUT matter and energy together are always conserved.
When an object experiences friction, the kinetic energy of the atoms or molecules increases, thus thermal
energy increases.
Energy from the sun is converted to chemical energy in plants and animals.
Fossil fuels were formed from the remains of ancient plants and animals.
Examples of fossil fuels are coal, natural gas, and petroleum.
The potential chemical energy from fossil fuels is released and transformed when fossil fuels are burned.
Power is the rate at which work is done, or the rate at which energy is transformed.
Power is calculated by dividing the amount of work done or energy converted by the time it took.
The unit of power is the watt (W). ---- 1W = 1Joule /second --- Power = (Force x Distance) / Time