do huge things move slowly because theyr'e huge, or because they exist slowly?

I’m not even sure how to articulate this question without sounding like a lobotomized rhesus monkey that’s just been through physics 101.

The other day I was imagining what it would be like if a huge creature - perhaps a Godzilla-sized monster, or even a person who suddenly found themselves blown up to huge proportions - existed in our atmosphere. I’m talking really HUGE - not just the size of a skyscraper, but big enough to stand with, say, one foot on virginia and one foot on tennessee.

Keeping this in mind, I started wondering - would this guy be able to do something like walk and jump around at the same speed that a normal-sized person would be? It’s hard to articulate what I’m asking - in general, large thigns are portrayed as being lumbering and slow. Is this simply a matter of perspective based on the difference between their sizes and those of tiny people, or do they evolve to be that slow? Again, failing to articulate, but I hope this makes some sense.

If our huge man wanted to, say, jump to Canada, would it be perceived as a big, lumbering motion to the tiny people on the ground, or would they perceive it to be as quick a motion as if they jumped from one square to another in a game of hopscotch?

Geometrically speaking, an ant, mouse, and a human are all big enough to stand with one foot on Virginia and one foot on Tennessee. In fact there’s a place out west where you can stand on 4 states.

I reckon you meant 1 foot in the center of each state. That means your monster’s stride would be equal to that distance, which would be something like (wild guess) 250 miles. Thus, if he takes 1 second to make a step, his foot would be traveling nearly a million miles per hour. The heat of friction and the shockwaves would probably kill everyone in both states. That’s just from 1 step, disregarding seismic or rotational effects upon the earth.

Long story short, it would be a big deal. Very big deal.

There are also issues of mass and inertia. A large object requires more energy to cause movement than a small object. Vespa moves faster than Kenworth. Large masses also need more time to slow them down because they have more kinetic energy. If I slam shut the discharge valve on an pump flowing 60 GPM through a 1" line, damage is unlikely. Do the same thing to a pump flowing 1000 GPM through a 5" line, and a repair bill will be the result.

Perhaps you meant to say that a Vespa may accelerate quicker than a Kenworth.

Scale effect works against such large land animals. If you make something 100 times as large it will have 10,000 times the strength due to muscle cross section. Unfortunately it will be 1,000,000 times as massive so it ends up being 100 times more difficult to just schlep itself around. The Amazing Spiderman has the proportional strength of a spider only if you are bad at math. If you scaled a spider up to human size it would probably be unable to walk let alone jump from building to building.

what is an interesting question is whether speed scales with size (in general). I suspect there is an optimal size for speed.

I think it would be perceived as such. Small sailboats or speedboats are easily mistaken as being faster than large ships like ferries and big container ships, even when the larger ones are in reality moving much faster. Small creatures like mice or flies and bees zipping by are also seen as quick even though they’re not particular fast compared to say humans.

It may look slow an lumbering to us people, but consider this: if you mean this giant walks at a pace that’s the same as us, say 1 second per step, then he takes the step from Virginia over Tenesse to Arkansas, he’s really moving incredibly friggin’ fast. What’s that, say, 1200 miles per second? The space shuttles don’t move that fast!

There’s physical considerations to take into account, too. You can get a good idea of how fast a biped can walk by saying treating the legs as pendulums, which oscillate at a natural frequency proportional to sqrt(g/l) (l being the length of the creature’s legs), and that the biped’s stride length is also proportional to l. So therefore the “natural walking speed” for such a creature scales proportionally to the square root of their size; a giant who was 100 times larger than you could only walk 10 times as fast.

As Padeye points out, muscular strength, being based on cross-sectional area, increases as the square of linear dimensions, while mass, being related to increases in all three dimensions, increases as the cube. A creature of the size you postulate would not be merely slow, it would be utterly immobile. Even a creature the size of a Blue Whale would probably be unable to move at all on land - unless perhaps it were something like an enormous slug.

It’s not totally relevant, but keep in mind the big vs. fast issue only exists planetside. Keep in mind the Earth is moving in space somewhere around 30,000 mph.

[sub]Note: that is only a back of the envelope calculation to get the order of magnitude.[/sub]

Though it can be interesting to ignore this constraint, you’re probably aware that such a creature can’t exist unless he’s made out of far different materials than are known on earth and/or normal physical laws can be temporarily suspended.

Are you the one that keeps pissing on Pennsylvania?

:smiley: