Quote:
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Originally Posted by Tassel
Quote:
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Originally Posted by nutant gene 71
So if you weigh on earth 100 kg (Earth scale), your weight on Earth (at 9.8 m/s^2) is 980 N. If G is 5 times greater on Jupiter, your Jupiter weight woud be five times Earth’s N (times 23 m/s^2), so you would weigh 23 * 4900 N, which now makes you in Newtons force = 112,700 N. However, that is incorrect. Your weight on Jupiter is the same as it was before we (hypothetically) discovered it had a different G, so the correct weight on Jupiter is only 100 kg * 23 m/s^2, so you would weigh 2300 N. So you see, it doesn’t work, which is why I avoided this analogy.
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You are so confused it is becoming painful to read this thread.
W = mg
The mass of an object is 100kg.
The weight on Earth is: 100kg * 9.8m/s^2 = 980N
The weight on Jupiter is: 100kg * 23m/s^2 = 2300N
G is required to calculate the mass of Jupiter. If we discovered G were different at Jupiter, then we'd realize we had always had Jupiter's mass wrong. We'd recalculate Jupiter's mass and find it was much lower than we thought. You've pointed this out seemingly hundreds of times: GM remains constant. Therefore, acceleration due to gravity remains constant. The mass of the object in question remains constant. If m (mass of the object) and g (acceleration due to gravity) are the same before and after the "discovery" that we were wrong about G, guess what? W is the same before and after the "discovery". If you'd just take 30 seconds and walk through the calculations step-by-step instead of running around randomly multiplying everything by 5, you'd see this. |
-- bold mine
Exactly! So what is Jupiter's "kilograms" per my bold? Is 100 kg on Earth still 100 kg on Jupiter, in (assumed) 5 G? Or is it this same mass now 20 "kg" per Jupiter's 5X (Earth) G? Don't you see that in Jupiter's greater graivtational G "proportional" each kilogram is now five times greater? Of course the end result is the same mass with 100 kg, but can you see the qualitative difference here, or not?
Don't get frustrated about it, but think of what is happpening if a body's gravitational G is different: to arrive at the same kilograms of mass we use on Earth, the "kilograms" of a different G world
have to be adjusted for the higher G. There is no getting around this, and this is why the mass acts differently there, because (per above example) each kg.-Earth is now equivalent to 0.2 kg-Jupiter. This is not so confusing, and I'm sure if you can understand Relativity, you can understand a variable G, in fact it's easier!