Work and Energy - العلم نور

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الاثنين، 12 سبتمبر 2016

Work and Energy


Work and Energy
                      
Work :

What is work?

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 .

work is the application of a force over a distance.

w = fS.s work  formula is  :

w = work
 f = forc
S=distance

  


Example :
 moving an object with a force of one newton for a distance of one meter equal one joule of work .

   joule is a unit that measures work





work – Energy principle :
the change in the kinetic Energy of an object is equal to the net work done on the object.

Energy :
what is 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 m v2

Types of energy :
there are two types of energy in many forms :
kinetic  energy = Energy of motion -
potential energy = Stored Energy -














Examples of kinetic Energy and potential energy  :



Power:
what is power ?

Power is the rate at which work is done.


It is the work/time ratio. Mathematically, it is computed using the following equation.

Power = Work / time

or

P = W / t

The standard metric unit of power is the Watt. As is implied by the equation for power, a unit of power is equivalent to a unit of work divided by a unit of time.

Thus, a Watt is equivalent to a Joule/second. For historical reasons, the horsepower is occasionally used to describe the power delivered by a machine. One horsepower is equivalent to approximately 750 Watts.










         We hope that you like this topic .



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