In 2g, would jumping be harder?

[DaveC426913]

TL;DR

The same effort would get you only half as high. But otherwise would you notice?
Doesn't the whole process scale down?

Let's say in a nice leisurely challenge, I jump a foot. i.e. my feet peak at one foot off the ground.

If I were in 2g and I expended the same effort, I should jump a mere six inches.
Would this be equivalent all aspects?
i.e I wouldn't damage myself any more in the second jump than the first (assuming I don't fall over).

 

[Ibix]

You have to bend your knees then straighten to jump. During that process you would feel like you weigh twice as much as normal (don't skip leg day!). And you would only be in the air for 70% as long as in 1g, which would probably feel odd.

 

[sophiecentaur]

TL;DR: The same effort would get you only half as high. But otherwise would you notice?
Doesn't the whole process scale down?

Would this be equivalent all aspects?

The energy needed to lift mass from zero height to h height (ending up stationary) would be
W=mgh
m=mass
g is gravity and mg is the weight
h is height
That formula tells you that if you double g you will only attain half h which would imply that your "scaling down" would apply

BUT that's in an ideal and theoretical situation and doesn't apply to our body and the physical work we expend.

Your body is not 'ideal' so that formula would not be an exact prediction over a range of conditions. It's too simple a model for human jumpers. We use multiple gears on a bicycle to match the slope of the road to get the best out of your legs. If the W=mgh formula applied all the time , we wouldn't need gears.

There are many studies of how humans perform physical exercise and it's a very complex business.

 

[A.T.]

The same effort would get you only half as high. But otherwise would you notice?

Are you interested in physics or biology?

If physics: I strongly suggest replacing the human with a simple jumping mechanism, and analysing that.

If biology: Human biomechanics is complicated, and asking about perception adds another level of complexity. But if you just ask a yes/no question, then of course you would notice. Even just standing still in 2g would cost you much more energy than in 1g. Probably not just twice as much, but even more, because we are biomechanically optimized for 1g.

 

[DaveC426913]

Thanks guys. This thought was driven by someone posing the question as to whether jumping would be "impossible" in 2g.

My first thought was that a six inch jump in 2g would be the same on your body as a one foot jump in 1g.

But upon reflection, I conclude it can't possibly as simple as that.

Simply looking at those two bodies standing still (a jump height of 0), it is obvious that, in 2gs a human would suffer from fatigue and pain in their back, legs and organs.

 

[sophiecentaur]

It would be like trying a stand jump with a 80kg backpack. Special Forces ‘run’ with that sort of load. When I did my mountain backpacking I kept the load to below 20kg and there was a distinct absence of ‘skipping over the hills’. Some billions of years of our evolution was based on regular human weight in 1g.

 

[BWV]

i.e I wouldn't damage myself any more in the second jump than the first (assuming I don't fall over).

Dont want to make too many assumptions from your pic, but for us of a certain age I am sure a 2G jump would damage something ;)

 

[DaveC426913]

Dont want to make too many assumptions from your pic, but for us of a certain age I am sure a 2G jump would damage something ;)

I am at that age where I can damage something if I sleep on the wrong pillow.

 

[sophiecentaur]

I am at that age where I can damage something if I sleep on the wrong pillow.

Even under 2g?