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Law of conservation of energy derive formulas

Posted by Anmol Kushwaha 5 years, 8 months ago

CBSE > Class 09 > Science

5 answers

Yuvika Mourya 5 years, 8 months ago

By these all equation we got the conclusion energy can't be created nor destroyed

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Yuvika Mourya 5 years, 8 months ago

Please reply whether you understood or not?

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Yuvika Mourya 5 years, 8 months ago

Now at last but not least, ?the body is at bottom of the cliff so the PE is 0 becoz his final v is 0. KE is1/2mv^2 now again take equation of v^2-u^2= 2gh here we have took h becoz he had covered hieght of cliff. Therefore again equation is v^2=2gh now keep it on KE equation therefore it is mgh. Mechanical energy is KE+PE. which = to mgh

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Yuvika Mourya 5 years, 8 months ago

Now, at the middle of the hieght of the cliff at B point when he travel distance s. PE will be mg(h-s) therefore it is mgh - mgs and KE is 1/2mv^2 <- this we all know but v^2-u^2=2gs here we will take s not h because body have not covered whole hieght yet. Therefore as u=0, equation will v^2 = 2gs now keep this value v^2 in kinetic energy's formula so it will be = to (1/2m)into(2gs) so according to this statement KE is mgs. Therefore machenical energy is KE +PE that is mgs +mgh-mgs =mgh.

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Yuvika Mourya 5 years, 8 months ago

At top of the cliff if body is standing let it be 'A'. Then Ke will be 0 because the body is at rest so v=0 therefore ->If KE =1/2 mv^2 then KE will be 0. and potential energy will be muh. Therefore machenical energy = KE +potential energy that is mgh

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