Question

When we stand still and erect with say a 20kg load on our head, after sometime we will feel tired - earlier than if we stand without any load. This means, we are spending more energy with load on our head. From where does a non-living thing like table manages that energy.

Answer 1

Explanation:

Total work done by the body is converted in energy. Since there is no displacement in the body when they are kept at a point in rest, no extra energy required to maintain the load. For any living thing the matter is different. To maintain the load, an upward force is always working, which comes from our muscles by the cellular action and hence we get tired.