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ENERGY
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| "The ability of a body to perform work is called Energy". | ||||
| A body cannot perform work if it does not posses energy.A body cannot perform work more than the amount of energy. | ||||
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It is a scalar quantity. | |||
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UNITS
OF ENERGY
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| (i)
Joule (ii) Calorie [NOTE: 1 Calorie = 4.2 joule.] (iii) KWatt-Hour |
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TYPES
OF ENERGY
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There
aree numerous types of energy such as: Heat Energy Light Energy Sound Energy Nuclear Energy Chemical Energy
Electrical Energy
Solar Energy Wind Energy Kinetic Energy Potential Energy etc.
etc. |
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POWER
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"The
rate of work done of a body is called Power".
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AVERAGE
POWER
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| Average power of a body doing work is numerically equal to the totla work done divided by the time taken to perform the work. | ||||
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MATHMATICALLY
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Power
= Work done/time
Power = Work/t but [work = Fd] therefore Power = Fd/t |
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UNITS
OF POWER
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(i) watt
[1 watt = 1joule/sec ] (ii) Kilo watt [1Kw = 1000 watt] (iii) Mega watt (Mw) [1Mw = 106 watt] (iv) Horse power [1Hp = 746w] |
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| POTENTIAL ENERGY | ||||
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INTRODUCTION
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| Energy stored by a body by any means is called "Potential Energy". | ||||
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DEFINITION
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| "The energy stored by a body due to its position in gravitational field is known as ‘Gravitational Potential Energy’". | ||||
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FORMULA
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| Consider
a body of mass "m" placed at a height of "h" from the
surface of earth. Force = Weight = W but displacement (d) = h |
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Work
done = Fd
OR Work done = Wh [but W = mg] |
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| work
done = mgh We know that the work done in lifting the body is stored in the body in the form of Potential Energy. Thus P.E. = mgh |
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| For latest information , free computer courses and high impact notes visit : www.citycollegiate.com | ||||