4 ms·

Your correction is wrong... The size of the two objects is irrelevant. The only variables are their respective masses and the DISTANCE between them. If it's wo

Your correction is wrong... The size of the two objects is irrelevant. The only variables are their respective masses and the DISTANCE between them. If it's worth correcting people, it's worth correcting them correctly... Don't you agree? Also... The previous poster was pretty obviously talking about the constant of Gravitation (https://en.m.wikipedia.org/wiki/Gravitational_constant https://en.m.wikipedia.org/wiki/Gravitational_constant). His way of phrasing it is a common English shorthand that I see frequently enough that it's a well understood usage. They may not have used precise language, but their phrasing was definitely less misleading than your (incorrect) correction.

jacksnipe 5y ago
I assumed the gp was thinking about 9.8m/s^2 — because on the English speaking non-physics-expert world, this is called the acceleration due to gravity. You’re right that it’s distance, of course, but I was coming from a place of trying to be helpful, and thought that if they were talking about terrestrial physics, it’d be easiest to imply it depended on the size of the earth (which determines our distance from it) and your height.
- ummonk 5y ago
  That’s not something that could change based on experiment though. We define standard gravity as 9.80665 m/s^2 but the actual value will vary considerably based on location on the earth.
- SkittyDog 5y ago
  I don't buy that you were coming to this from a place of trying to be helpful. I know that here on HN, we're supposed to assume good motives in other posters, but I just can't do it, here. I think you were trying to score points, and get an ego fix by correcting someone else. Not so much fun when someone else dunks on you, though, is it?
ummonk 5y ago
It’s only dependent on the mass of the other object, not the mass of the object whose acceleration we’re measuring.
- SkittyDog 5y ago
  Objects can and do change their mass. Sometimes that mass changes over the course of the acceleration process (e.g., rockets). The mass of the accelerating object is absolutely a variable.

jacksnipe 5y ago

I assumed the gp was thinking about 9.8m/s^2 — because on the English speaking non-physics-expert world, this is called the acceleration due to gravity. You’re right that it’s distance, of course, but I was coming from a place of trying to be helpful, and thought that if they were talking about terrestrial physics, it’d be easiest to imply it depended on the size of the earth (which determines our distance from it) and your height.

ummonk 5y ago
That’s not something that could change based on experiment though. We define standard gravity as 9.80665 m/s^2 but the actual value will vary considerably based on location on the earth.
SkittyDog 5y ago
I don't buy that you were coming to this from a place of trying to be helpful. I know that here on HN, we're supposed to assume good motives in other posters, but I just can't do it, here. I think you were trying to score points, and get an ego fix by correcting someone else. Not so much fun when someone else dunks on you, though, is it?

ummonk 5y ago

It’s only dependent on the mass of the other object, not the mass of the object whose acceleration we’re measuring.

SkittyDog 5y ago
Objects can and do change their mass. Sometimes that mass changes over the course of the acceleration process (e.g., rockets). The mass of the accelerating object is absolutely a variable.