amit sharma and mohineesh sharma
DESCRIPTION
biologyTRANSCRIPT
The intuitive meaning of work is quite
Different from the scientific definition of
Work . In everyday activity , the term
‘work’ is used equally for mental and physical work involving muscular force.
In physics , the term work is used in special technical sense and has a much more precise definition .
DEFINITION When force is acted on a body and the
body get displaced through a distance then work is said to be done .
There are two conditions that must be
satisfied in work done by a body .- A force is applied on the object .- The object be displaced from its
original position.
Mathematically Work is defined as the product of force acting on the body and
displacement is produced in the body . Formula of work is :
W = FScosθ
2 of 10
Peter Loader @ TLT
θ (Angle in degree) COSθ O 1 90 0 180 -1
CASE 1 When the direction of force and displacement are
same . we know W = FScosθ (θ = 0 [in degree] ) W =FScos180 W =FS* 1 W =FS Example- when a body is dropped from a certain
height.
SI Unit SI unit of work = SI unit of force * SI unit
of displacement Joule (J) = N * m J = Nm
CGS Unit of work = CGS unit of force * CGS unit
displacement erg = dyne * cm erg = dynecm
We know 1j =1N * 1m 1j = 100000 dyne * 100
cm 1j = 10000000 erg
1 kilo Joule = 1000 Joule
1 Mega Joule =1000000 Joule
Energy of an object is defined as its capacity for doing work and it is measured
by the total quantity of work it can do. OR Ability to do work is called energy .
SI unit of energy is same as the SI unit of work. i.e. joule (J).
There are many types of energy but Kinetic energy and Potential energy have mathematical .
Solar Energy Heat Energy Light Energy Chemical Energy Wind Energy Hydro Energy Sound Energy Electric Energy Magnetic Energy Tidal Energy Nuclear Energy Mechanical Energy
Solar Energy The energy radiated
by the sun is called solar energy used in photosynthesis .
Heat Energy When energy
released by gas , oil , petroleum products is called heat energy .
Light Energy Energy which
produce sensation of vision.
Chemical Energy Energy which is
produced by fuels , chemicals etc.
Wind Energy Energy produced by
moving air .
Hydro Energy The energy
produced by flowing water is called hydro energy.
Sound Energy Energy which
produced by the vibration of object and produced sensation of hearing .
Electric Energy Energy Produced by
flow of charge .
Magnetic Energy Energy produced by
magnet .
Tidal Energy Energy produced by
high and low tides .
Kinetic Energy The energy in a
body by virtue of its motion is called Kinetic energy .
Potential Energy The energy in an
object by virtue of its position or configuration is called its potential energy .
Nuclear Energy The energy which
produced by nuclear reactions is called nuclear energy .
Mechanical Energy The sum of kinetic
and potential energy is called mechanical energy .
Mathematical definition of kinetic energy is equal to half the product of mass and square of velocity .
Mathematically potential energy is
equal to the product of mass , acceleration due to gravity and height .
P.E = M * g * H
The conversion of energy from one form
of energy to another form of energy is called energy transformation .
According to law of conservation of energy can neither be created nor be destroyed only it can be destroyed from one form of energy to another form of energy .
Rate of doing work done is called power .
OR Work done per unit is called power . W =Work Done T = Time P = W / T
si unit of power = si unit of wok / si unit time
W = J /SI Unit of power is Watt [ W] and is
named in the honor of James Watt .
Practical unit of power or a unit which is exclusively used in engineering or in automobiles is called horse power (hp) .
1 hp = 746w
It is defined as the ratio of total workdone by the body to the total time taken by the body
AP = Total workdone / Total time
Commercial unit of electric energy is Kilowatt-Hour (KWH).
Commercial Unit of electric energy i.e. KWH is used in household industries for measuring electric energy consumption .