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[sudgy]

That's a statics equation, as nothing is moving, of a beam at a fixed length. Your result will be in the form of torque, because the lower arm has length to it.

Well, it was in my physics book.  I saw the answer, and I did everything exactly as it did but I had an extra variable (the weight of the arm), so I wasn't able to solve it.

[AHoppy]

That's a statics equation, as nothing is moving, of a beam at a fixed length. Your result will be in the form of torque, because the lower arm has length to it.

Well, it was in my physics book.  I saw the answer, and I did everything exactly as it did but I had an extra variable (the weight of the arm), so I wasn't able to solve it.

The weight of the arm complicates it... You would need to find the center of mass of the arm (which depending on how you are modeling the arm, can be fairly simple to quite complex) and then you get a moment from that.  In general, what I've found in text books is if it doesn't give you something, you need to make an assumption about it.  In high school physics (if I recall correctly, you are doing high school physics sudgy?) I would not be surprised that you are ignoring the mass of the beam.  I don't recall doing much with finding centers of mass until college level statics. 

Either that or you could find a density of bone/muscle/human arm in the back of the book and calculate a mass from that. 

[Witherweaver]

The question should be worded to indicate you don't need to to the arm's mass into account.. like it should have asked what force was exerted to hold the ball up, or what force the ball's weight was exerting, or something to that effect.

[sudgy]

I am doing advanced high school physics (which I've heard is actually partly beginning college level).  In the example before this question, they had multiple things not mentioned in the question be a part of the answer, including something similar to the arm.  Although, that did have a well defined center of mass.

This was just a practice problem so it didn't matter whether or not I got the question right, anyway.

[GeoLib]

I am doing advanced high school physics (which I've heard is actually partly beginning college level).

Depends on which high school and which college you are talking about.

This was just a practice problem so it didn't matter whether or not I got the question right, anyway.

Any reasonable teacher should give you credit for an answer that can trivially be shown to be right by plugging in 0 for the mass of the arm.

[Ozle]

Don't make me go and start a Physics thread like I did maths now.....

[Polk5440]

Any reasonable teacher should give you credit for an answer that can trivially be shown to be right by plugging in 0 for the mass of the arm.

Only if the answer is correct if the mass of the arm is non-zero, too.

[Kuildeous]

Why is it that talking about a belligerent drunk guy in an edamame costume is the only time that I can get uproarious laughter from saying, "He puts the FU in 'tofu'"? That should be a universal greeting or something.

[AndrewisFTTW]

[GendoIkari]

I've seen pretty much every CH original video. I'm really annoyed that they've pretty much stopped making good stuff within the last year. I really miss all those actors/characters that they had.

[pacovf]

The De Beers diamond monopoly is really old, well documented news. Actually, it's so old news that it is close to not being true anymore for close to two decades. Mainly, Russia happened. Depending on how the market stabilizes, prices might actually start to drop!

[Kirian]

Any reasonable teacher should give you credit for an answer that can trivially be shown to be right by plugging in 0 for the mass of the arm.

Only if the answer is correct if the mass of the arm is non-zero, too.

I disagree, on the assumption that the student expresses the assumption and/or indicates how the answer would change if the arm had mass.

[Archetype]

[GeoLib]

Any reasonable teacher should give you credit for an answer that can trivially be shown to be right by plugging in 0 for the mass of the arm.

Only if the answer is correct if the mass of the arm is non-zero, too.

I disagree, on the assumption that the student expresses the assumption and/or indicates how the answer would change if the arm had mass.

It depends. If the problem was supposed to be for a zero-mass arm, and giving the arm mass makes it more difficult and then the student gets an answer that isn't the right way of dealing of an arm with mass, but the part for the massless arm is right, I would certainly give them credit. I mean, if you were trying to see if they could solve one problem and then in their solution they answer a harder problem and demonstrate they know how to solve the original problem, they should get credit. I would also, of course, note to them that their solution was not correct (and where the error was).

[Kuildeous]

I'm a little creeped out by my friend's Facebook account. He got married 5 years ago, and they both deleted their FB accounts and created a joint account. It has both their names on it. When I see a status update, I rarely know which one posted it, which gets a little awkward when they talk about their father being in the hospital. Wait? Which one? How do I ask this without looking inconsiderate?

Today is their "birthday." Not the husband's birthday. Not the wife's birthday. The FB birthday is actually their anniversary date. So there's even more confusion as people send happy birthdays to them. They didn't know which one was having the birthday, and it turns out that they were wrong anyway.

And then there's also the implications of what a shared FB account means. It sounds more like trust issues to me, but I'm sure it is viewed as romantic by others.

It's just further evidence that he and I have drifted apart. I definitely would not picture him doing that 20 years ago. But he seems happy with it now, so more power to him.

[theory]

That's uh, definitely unusual.

[Witherweaver]

I'm a little creeped out by my friend's Facebook account. He got married 5 years ago, and they both deleted their FB accounts and created a joint account. It has both their names on it. When I see a status update, I rarely know which one posted it, which gets a little awkward when they talk about their father being in the hospital. Wait? Which one? How do I ask this without looking inconsiderate?

Today is their "birthday." Not the husband's birthday. Not the wife's birthday. The FB birthday is actually their anniversary date. So there's even more confusion as people send happy birthdays to them. They didn't know which one was having the birthday, and it turns out that they were wrong anyway.

And then there's also the implications of what a shared FB account means. It sounds more like trust issues to me, but I'm sure it is viewed as romantic by others.

It's just further evidence that he and I have drifted apart. I definitely would not picture him doing that 20 years ago. But he seems happy with it now, so more power to him.

Sounds like it's time to unfriend!

[Kirian]

Yeah, shared FB accounts seems like a really, really weird thing.

I bet it fucks up FB's advertising algorithms something good though.

[soulnet]

Real friends are the ones that say happy birthday even if they cannot get the date from Facebook.

Can't they maintain their own profiles AND get a joint one for the romantic stuff?

[Witherweaver]

Real friends are the ones that say happy birthday even if they cannot get the date from Facebook.

Can't they maintain their own profiles AND get a joint one for the romantic stuff?

Fixed that for you.

[Kuildeous]

That's the really weird thing. They did have separate accounts. I even accepted her friend request because I'll generally accept the friend request of a friend's spouse if they want to friend me…at least if I've met them.

So they had individual accounts and then decided it was easier to have just one. I don't recall if they actually deleted both or deleted one and just changed the remainder. But it was a very conscious decision they made to have only one account with both their names on it.

Hopefully they won't divorce, but if it should happen, then the FB account would become either very amusing or very tragic.

[eHalcyon]

It would be like those facebook accounts that get turned into memorials...

[enfynet]

Why does it matter? Facebook is used less for communication and more for advertising narcissism. I have a Facebook page for my little golf club hobby, but I don't have a personal page full of "look at me" stuff. Not so long ago, joint/family emails were the norm. Who decided this digital media was going to restrict people to individual use? As a society we are moving away from community, and in doing so become numb to the world around us. It's a very cold place to be.

[eHalcyon]

Why does it matter? Facebook is used less for communication and more for advertising narcissism. I have a Facebook page for my little golf club hobby, but I don't have a personal page full of "look at me" stuff. Not so long ago, joint/family emails were the norm. Who decided this digital media was going to restrict people to individual use? As a society we are moving away from community, and in doing so become numb to the world around us. It's a very cold place to be.

Believe it or not, some people do use Facebook for communication and catching up with old friends.

As for community, I don't think it means that the individuals should be subsumed.  We may all be Wandering Winder, but we still keep separate accounts here.  For people who aren't all the same person, how much weirder is it that they merge into one account?  I think Kuildeous' point is that their adoption of a single Facebook page kind of suggests that this married couple are no longer really individuals.  That's highly unlikely of course -- they probably still have individual interests, some friends that the spouse can't stand, etc. -- but the single Facebook page recalls the trope of the couple that is always joined at the hip and seem to have melded into one being.

[Polk5440]

For people who aren't all the same person, how much weirder is it that they merge into one account? .... recalls the trope of the couple that is always joined at the hip and seem to have melded into one being.

That is an ideal for some people, not a trope.

Married couples often merge all their assets and accounts (e.g. bank accounts). Why should Facebook be different? I know couples who use one page jointly because they only want to use it for family updates (much like the family email account enfynet mentioned earlier.)

Facebook is a tool to be used, and it can absolutely be successfully used jointly (though I refuse to use it at all).