>Well why then when you support the weight do you expend so much energy, to the point where, due to fatigue you can no longer support the weight.
>
>I ask again what is the difference between you and the post.

Didn't I reply to that already?

If you can theoretically do a certain process with a certain amount of energy, it is always possible to do it with more energy - wasting energy, in other words.

For instance, you can move an object horizontally with a lot of force, or you can make the required force less, by decreasing resistance. In theory, this resistance can be close to zero.

For instance, you can use a fluorescent light bulb that converts close to 100% of the electrical energy, or you can use an incandescent bulb, where the percentage (the efficiency) is much closer to zero. (The remaining energy is converted to heat - increasing entropy).

For instance, you can burn fuel at a high temperature, as in a diesel motor, or in a lower temperature. At the lower temperature, less useful energy can be obtained. (See: Carnot cycle; heat engine.)

For instance, you can paint your light bulb with some color; it might look neat, but the percentage of usable light will be smaller (some part of the light will be absorbed, and converted into heat).

For instance, you can put a post to support a weight (zero fuel required), or you can use muscular energy (fuel, or food, required > 0).

In almost all processes where energy is wasted, the wasted energy becomes heat.