A person feels hungry even though he doesnot do any work give reason

See the explanation below.

Explanation:

The human body as well as that of any mammal uses a function known as metabolism. Which is able to convert energy from food into useful energy for different activities. These activities can be physical or bodily. The activities of the body are those necessary to maintain the body temperature above 36 [°C] this same temperature keeps the blood at sufficient temperature to facilitate the functions of pumping blood through the veins and arteries of our body.

In such a way that when the body feels hungry, this is a mechanism that tells us that our body requires energy from food, to maintain normal body energy levels. For this reason athletes need a large caloric intake of food, to be able to meet the standards of the competition and others.

it is called kinetic energy

this could be newton#'s law of cooling. the cooling curve is exponential