Definitions Work
can be defined as transfer of energy. In physics we say that work is done on an
object when you transfer energy to that object. If one object transfers (gives)
energy to a second object, then the first object does work on the second object.
Work is the application
of a force over a distance. Lifting a weight from the ground and putting it on
a shelf is a good example of work. The force is equal to the weight of the object,
and the distance is equal to the height of the shelf (W= Fxd). Work-Energy
Principle --The change in the kinetic energy of an object is equal to the
net work done on the object. Energy
can be defined as the capacity for doing work. The simplest case of mechanical
work is when an object is standing still and we force it to move. The energy of
a moving object is called kinetic energy. For an object of mass m, moving with
velocity of magnitude v, this energy can be calculated from the formula E= 1/2
mv^2. Types
of Energy There
are two types of energy in many forms: Kinetic
Energy = Energy of Motion Potential
Energy = Stored Energy Forms
of Energy Solar
Radiation -- Infrared Heat, Radio Waves, Gamma Rays, Microwaves, Ultraviolet Light Atomic/Nuclear
Energy -energy released in nuclear reactions. When a neutron splits an atom's
nucleus into smaller pieces it is called fission. When two nuclei are joined together
under millions of degrees of heat it is called fusion Electrical
Energy --The generation or use of electric power over a period of time expressed
in kilowatt-hours (kWh), megawatt-hours (NM) or gigawatt-hours (GWh). Chemical
Energy --Chemical energy is a form of potential energy related to the breaking
and forming of chemical bonds. It is stored in food, fuels and batteries, and
is released as other forms of energy during chemical reactions. Mechanical
Energy -- Energy of the moving parts of a machine. Also refers to movements in
humans Heat Energy
-- a form of energy that is transferred by a difference in temperature What
is Power Power
is the work done in a unit of time. In other words, power is a measure of how
quickly work can be done.
The unit of power is
the Watt = 1 Joule/ 1 second. One
common unit of energy is the kilowatt-hour (kWh). If we are using one kW of power,
a kWh of energy will last one hour. Calculating
Work, Energy and Power WORK
= W=Fd Because
energy is the capacity to do work , we measure energy and work in the same units
(N*m or joules). POWER
(P) is the rate of energy generation (or absorption) over time:P
= E/t Power's
SI unit of measurement is the Watt, representing the generation or absorption
of energy at the rate of 1 Joule/sec. Power's unit of measurement in the English
system is the horsepower, which is equivalent to 735.7 Watts.
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