I suppose that counting n elements should be linear time, right? It takes double time to count double number of elements. But in the real world, it is faster and O(1) to weigh elements and find out the total weight so in the real world you can count n elements O(1) just by putting all the elements on a scale and dividing by the weight of one elements.
Is my reasoning correct that physically it is possible to speed up a calculation by this trick, or am I mistaken?