CBSE BOARD X, asked by maitridesai, 1 year ago

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Total Energy during a physical or chemical process is conserved. If energy can neither be created nor be destroyed then why is there a need to conserve energy ?

Answers

Answered by Mukunth27
1
It is to be noted that, energy is always remain conserved, the only problem is when it is converted from usable form to unusable form, we cannot obtain energy restored.

A best example for it is,
When you scratch something hardly, you do mechanical work on it with your muscle energy which is transferred into friction of the scratched object but it turns into unusable form of heat and sound produced by it.

It is an unnoted example in any book.

Mukunth27: welc
Answered by Divyanshu111111111
1
Energy can be converted from one form to another, though. Mechanical energy,
such as the kinetic energy of motion, can be converted to heat energy, for
example in the heating of a car’s brakes when it slows down. Chemical energy in
the gasoline of the car can be converted into both heat energy in the exhaust
and heating the engine, and into mechanical energy to move the car. Potential
energy, such as the gravitational potential energy stored in an object which is on
a high shelf, can be converted into kinetic energy as the object falls down.
Electrical energy can be converted to heat or mechanical energy or sound energy
in a variety of useful ways around the house using common appliances.
It is often the conversion of one form of energy to another which is the most
important application of this rule. Often predictions of the behavior of physical
systems are very much more easily made when using the idea that the total
amount of energy remains constant. And careful measurements of different kinds
of energy before and after a transformation always show that the total always
adds up to the same amount.
Historically, of course not all the forms of energy were known to begin with.
Scientists had to keep inventing more forms to keep the law of energy
conservation true. If that process had gotten too messy or complicated to make
sense, we would have had to give up the law.
One very interesting feature of energy is that other forms can be converted into
rest mass and back again (particle physicists do this every day in their
accelerators). Einstein’s E=mc^2 gives the relationship between the rest mass of
a particle (measured in standard mass units) and the amount of energy that
corresponds to (measured in standard energy units). It even applies to other
systems where particles are neither created nor destroyed. If a box contains
some air at a temperature, and then is warmed up, it will become ever so
slightly more massive because of the extra energy given to it. You can call that
rest mass of the whole box or the mass equivalent of the kinetic energy of the
particles in it- nature doesn’t care what names you give it.
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