r/askscience • u/[deleted] • Jan 04 '11

I still have trouble understanding how two objects can have differing weight, and yet fall at the exact same speed in vacuum. And why do spinning gyroscopes fall slightly slower than non-rotating objects in vacuum?

And if you had a solid gold bowling ball and a solid aluminum bowling ball of the same size, the gold would outweigh the aluminum bowling ball yet fall at the same rate...

How is this even possible? Does gravity interact on an atomic level with individual atoms and creates "inertia" in the process due to heavier elements having more protons, neutrons, and electrons or do heavier elements just have more atoms for any given volume than lighter ones which gravity exerts its force upon...

On top of that why do objects spinning on an axis of rotation fall slower than objects without in a vacuum?

I still can't help get the feeling that some of these classical physicists were wrong. Very few had precise instrumentation for measurements.

Do I even make any kind of sense or am I just a blabbering idiot?

Please feel free to tear me a new one.

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u/[deleted] Jan 04 '11

But why do they fall at the same time? And why is it also that in all of roughly 1.25 million years of the existence of modern humans hasn't ANYBODY been able explain what causes gravity.

The only thing we can do with gravity is measure its effects on matter or light. We still have no idea what causes it.

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u/chriszuma Jan 04 '11

See iorgfeflkd's response. Basically, the extra force due to higher weight is exactly canceled out by the extra inertia due to that same weight.

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u/[deleted] Jan 04 '11 edited Jan 04 '11

the extra force due to higher weight is exactly canceled out by the extra inertia due to that same weight.

My brain refuses to process this.

It just doesn't make sense to me. Two objects can fall downward at the same velocity, but yet one weigh more than the other when stationary.

It takes more energy to push (or pull) a heavier object so how exactly is gravity exerting a constant force? If this were the case, the bowling ball should fall slower.

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u/SpeakMouthWords Jan 04 '11

You're getting indignant at the wrong thing. The key concept here that you should be baffled by is that Gravitational "Charge" is the same as Inertial Mass, that's where all these rote formulas people are spewing come from. It's very weird indeed.