Eli5: does it require the same amount of energy to walk a loop, say in the mountains, with very uneven elevation changes and slopes,whether you walk it one direction or the other?
In: Physics
If you simply sum up the energy, yes.
But that’s not the whole story. You said, “Walk”. When you walk, you can’t recover energy when going downhill. It gets wasted as heat, and you even have to use more energy to catch the energy and turn it into heat (i.e. to not roll down a hill and turn the energy into scrapes and bruises). Depending on the terrain, it can cost you more energy to go down than to walk on a flat plain.
Something similar happens when going uphill. It makes a difference if you walk up a slope or have to climb a near-straight wall.
Nothing is simple with the human movement apparatus, but as a rough estimate, you can say that the direction that has up-slopes and down-steps takes you less energy than the other way around.
Mathematically, yes. Whenever you go down in one direction, you must come up an equal amount before you can reach your starting point. Vice versa for moving up.
In reality, there can be some differences in how much effort you must put in (e.g. walking a long slope downhill is easier than having to scale down a vertical cliff) but the amount of elevation change you go through is the same in both directions.
Latest Answers