system
Given the following post, respond as if you're commenting on Reddit:
human
Why do large objects appear to move slow?

As in movies, when you see two giants battling, everything they do seems so slow. Or when you're watching a movie centered on ants or something and the humans appear to move slow. Why is this?
gpt
In movies, it's largely artistic, because we expect larger things to move slowly. We expect larger things to move slowly for a couple of different reasons. First, because we usually see large objects at long distances, and a large object moving fast at a long distance appears to be moving slower than a small object up close moving the same (linear) speed. Just think how small Mars appears to be moving in the sky, even though it is both massive and moving quite fast (compared, for instance, to something in low earth orbit, which appears to streak across the sky). Secondly, because of the issue of scale. The volume (and therefore, generally, mass) of objects goes according to the cube of the linear dimensions, so something that is twice as large (such as a giant compared to a human) has 8 times the mass. That means 8 times the inertia, as well, so we usually expect things that large to be slower both to start moving and stop. 

In reality, the appearance is mostly caused by distance. Larger objects farther away can appear to be just as big as a smaller object closer, but since it's farther away, even if it is moving at the same linear speed, its angular speed (which is how humans usually measure speed) is lower, so it appears to be moving slower.