According to the law of conservation of energy, energy can neither be created not be destroyed but it can transfer from one person to other!

But when a labour is working he uses his all energy in work but when he ate food he again gets energy !

This means energy can be created and can be destroyed

Asked by | 17th Sep, 2019, 08:29: PM

Expert Answer:

i) Law of conservation of energy states that - Energy can neither be created nor be destroyed it can be transferred from one form to another form of energy. 
ii) When we eat food the chemical energy in the food is stored in another form of chemical energy in our body (say in form of carbohydrates, glucose, fats, proteins etc.) So, basically energy from the food is converted to another form and get stored in our body and is not created. 
iii) When our body do a work the energy stored in our body is again converted to another form of energy while doing work. Let's consider your example where the labours are doing work (example construction of building). In this case, the energy stored in their body is converted to muscular energy for lifting the bricks, painting etc. So, in this case also the energy is converted from one form to another and not destroyed. 
Hope your doubt is cleared! Keep posting your doubts. All the Best!

Answered by Shiwani Sawant | 18th Sep, 2019, 11:11: AM