Is the force of gravity affected by an object's mass?

[BobG]

I'll get it started.
Math: 2 + 2 = ____ .

How can I possibly answer this with only scalar values? 2i + 2j will give a distinctly different answer than (.5i+.866j+1.732k) + (1.5i+.886j+k)

Another math problem:

If a class has 20 boys and 20 girls, how many students are in the class?
If a class has 20 boys and girls, how many students are in the class?

This was actually a subject for discussion during a higher headquarters inspection of a squadron's evaluation scenarios. They initially claimed the regulation requirement for at least three ground system and satellite system malfunctions per scenario meant three of each.

To their credit, they eventually realized how stupid that sounded - they weren't very good at vector math. I explained how it took two of each to equal a total of three ... at which point I was kicked out and higher headquarters decided the squadron was doing things just fine.

 

[mgb_phys]

This was actually a subject for discussion during a higher headquarters inspection of a squadron's evaluation scenarios. They initially claimed the regulation requirement for at least three ground system and satellite system malfunctions per scenario meant three of each.

Similair thing happened with 3G phone band license auction.
The auction rules said that bids had to be multiples of £1000, one bidder didn't have any competitors in their region but bid £2000 because the lawyers weren't convinced that £1000 was a multiple of £1000 !

 

[jostpuur]

Note that the people inside the moonbase not equipped with those special heavy boots just float. The end scene shows that the heavy boot effect has limited applicability. Slap someone in the back and off he goes, only to get hit by a meteor streaking through the moon's thick atmosphere. Documented!

I couldn't help noticing, that when youtube users comment like this:

well, at least I'm not the only one who had a scientific issue with this commercial.. ooh, check out the bad continuity.. they're inside - floating - yet things like nametags and ties will hang like they're in normal Earth gravity.. yup.. I'm a geek.. lol

Why are people walking on the surface, but floating indoors? How does that work? There's gravity on the moon, but only outdoors?

they get voted thumb down as dumb comments, but when somebody responds like this:

the asteroid thing wouldn't work and fedex doesn't ship to the moon, i don't think theyre going for accuracy

it gets voted thumb up as good explanation why one shouldn't get stuck with little scientific inaccuracies.

It could be that the collection of people who voted in this isn't very large, but caught my attention anyway.

 

[Jimmy Snyder]

Jimmy is retired, by the way. In case you couldn't tell.

Sadly no, I'm still working on my Master's thesis in Mathematics: The effect of a non-closed commutative arithmetic operator on a certain subset of the even integers. I already have a result. With proper care in choosing the subset, you can relax the condition that the operator be commutative.

 

[DaveC426913]

Jimmy is single and has no social life by the way. In case you couldn't tell.

 

[ideasrule]

Jimmy is single and has no social life by the way. In case you couldn't tell.

Why are we talking about Jimmy? Is this some running gag that I'm not getting?

 

[Jimmy Snyder]

Why are we talking about Jimmy? Is this some running gag that I'm not getting?

Jimmy's not threatened by ideasrule's question. Jimmy's happy for ideasrule.

 

[DaveC426913]

Why are we talking about Jimmy? Is this some running gag that I'm not getting?

Jimmy spent a lot of time writing that post (#66) is all.

 

[BobG]

Jimmy is single and has no social life by the way. In case you couldn't tell.

Jimmy's wife told you that, didn't she.

 

[Phrak]

Note that the people inside the moonbase not equipped with those special heavy boots just float. The end scene shows that the heavy boot effect has limited applicability. Slap someone in the back and off he goes, only to get hit by a meteor streaking through the moon's thick atmosphere. Documented!

Easy Peasy. Thems magnetic boots.

 

[Chi Meson]

I'll get it started.
Math: 2 + 2 = ____ .

I remember reading here on PF a couple of years ago, that sometimes 2+2=5, for large values of two.

 

[TheStatutoryApe]

I remember reading here on PF a couple of years ago, that sometimes 2+2=5, for large values of two.

Yes, Jimmy has laboured long and hard on errata page...
http://www.erratapage.com/

 

[George Jones]

Math: 2 + 2 = ____ .

Answer: 1.

Cosmology: Suppose there are two big bangs, and two big crunches. Then how many 'big' events are there?

Answer: 2.

 

[JasonRox]

The real idiots are those who believe the moon landing happened...

 

[ideasrule]

The real idiots are those who believe the moon landing happened...

...in a film studio?

 

[JasonRox]

...in a film studio?

It was filmed in a desert. Duh.

 

[AUMathTutor]

Oh God, can we not start this masturbatory science vs. religion thing again on these physics forums. Amen.

 

[mgb_phys]

It was filmed in a desert. Duh.

On Mars


[ps removed Arizona senator link to keep AUMathTutor happy]

 

[DaveC426913]

Oh God, can we not start this masturbatory science vs. religion thing again on these physics forums. Amen.

What does Moon hoaxing have to do with science versus religion?

 

[leroyjenkens]

The real idiots are those who believe the moon landing happened...

Haven't there been a few moon landings?

 

[DaveC426913]

Haven't there been a few moon landings?

Let's just keep things real here.

JasonRox and everyone else is just joking around about faked Moon landings. You won't find any serious Moon hoaxers in these parts. At least, not for long.

 

[Kaimyn]

As with anything, there's a good XKCD comic for it: http://xkcd.com/202/

 

[akrem]

SHOW THAT lo^3 is the volume of the cube,then lo^3*(1-v^2/c^2)^.5 is the volume viewed from a reference frame moving with uniform velocity V parallel to an edge of the cube.

 

[ideasrule]

What does this have to do with the Moon landings?

Just use the length contraction formula to figure out the dimensions of the cube in the moving reference frame. Also, homework questions should be posted in the "Homework and Coursework" forum, not in General Discussion.

 

[Eigenslam]

Reminds me of this video



Conversion factor fail

 

[leroyjenkens]

Reminds me of this video



Conversion factor fail

I think if you get them to acknowledge that .5 dollars is half a dollar and .5 cents is half a cent, they would be left with no option but to acknowledge .002 dollars and .002 cents aren't the same.

 

[Senjai]

im not even going to take the time to read through the statements and questions, Yes, their is gravity on the moon, and that TA is the stupidest person ever. That may be politically incorrect, however its the dramatic effect intended :P

 

[ideasrule]

Reminds me of this video



Conversion factor fail

Wow. For anybody reading this, you MUST watch this video. The full-length video (27 minutes long) is here:

http://verizonmath.blogspot.com/2007/08/original-recording-of-verizon-customer.html

 

[Galteeth]

Ok, an ignorant question: I understand that Newton's laws tell us that in a vacuum, two objects will fall at the same rate, regardless of mass.

But relativity says that gravity is the warping of space by mass. It would seem intuitive that something with more mass would cause more curving of space, hence greater gravitational "attraction."

Why is this not the case?

 

[ideasrule]

Um, it is the case. If Earth were more massive, it would pull on objects with more force.

 

[Galteeth]

Um, it is the case. If Earth were more massive, it would pull on objects with more force.

I meant the smaller objects. It would seem intuitively like since they have mass, that would produce some gravity which should slightly affect their attraction to the larger object. I know Newton's laws say this isn't the case. I was wondering why.

 

[BobG]

I meant the smaller objects. It would seem intuitively like since they have mass, that would produce some gravity which should slightly affect their attraction to the larger object. I know Newton's laws say this isn't the case. I was wondering why.

No, Newton's laws don't say this isn't the case. The force of gravity is directly proportional to an object's mass. An object's inertia, it's ability to resist that force, is also directly proportional to its mass.

You're mixing "attraction", which implies the strength of the force, and "acceleration" which is what's left over once you account for an object's ability to resist the force of gravity.