Question

(a) Explain the law of conservation of energy.

(b) Give one example of each energy transformation:-

(i) Heat energy to mechanical energy.

(ii) Mechanical energy to electric energy.

(c) A person is standing from 20 minutes with heavy weight on his head. Does he do any work or not? explain.

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Answer 1

Answer: a) According to the law of conservation of energy it means that "Energy can neither be destroyed nor be made" . It can be transformed from one form of energy to another form of energy.

b) When a car engine is working then the heat energy is transformed to the mechanical energy

c) When an electrical generator is working it converts mechanical energy into electrical energy

d) No the man is not doing any type of work as he is standing at only one place and not moving from one place to another. So the work done is zero

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Hope it helps you

Answer 2

Explanation:

If an object of mass m is moving with a velocity v, then its kinetic energy Ek is given by the expression, Ek = ½ mv2.