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/sci/ - Science & Math

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6247851 No.6247851 [Reply] [Original]

Well /sci/ are you smart enough to solve this simple problem?

>> No.6247854

>>6247851
Yes.

Redoing your homework problem in paint isn't going to fool us.

>> No.6247863
File: 27 KB, 400x400, 1388008339209.jpg [View same] [iqdb] [saucenao] [google]
6247863

>>6247854
You really think this is somebody's homework?

>> No.6247869

>>6247863

The specific data and wording gives it away. Fuck off and read your notes.

>> No.6247868

Something the some thing with the something so that the somethings become the samethings!

>> No.6247873

No force is required as no gravitational potential was specified. Now kindly fuck off.

>> No.6247872

>>6247863
It is so obviously homework it's ridiculous.

>> No.6247876

>>6247873
This.

For all we know it could be in interstellar space.

>> No.6247882 [DELETED] 

>>6247851
B to keep the weight up 93.1 N, A is 113.8 N

>> No.6247883
File: 22 KB, 400x400, 1388008962470.jpg [View same] [iqdb] [saucenao] [google]
6247883

>>6247882
> B < A
>mfw

>> No.6247885

>>6247882
Stop doing people's homework for them, especially when it's so potato grade.

>> No.6247888

>>6247863
How do you make a puzzle with out being specific?

You want the puzzle to look like >>6247868
this?

>>6247872
Make up a puzzle in a minute, people tell me ITS OBVIOUSLY HOMEWORK.
Honestly I don't know how to feel.

>>6247873
>>6247876
9.81, I really didn't think I would have to specify this


>>6247883
and here I though you were trying to ruse people.

>>6247885
why so mad?

>> No.6247895

>>6247888
>applying the basic concept
>no hidden tricks and no deep thinking involved
how is this puzzle?

>> No.6247899

>>6247895
>puzzle
bad choice of words on my part. Honestly people fail at basic math so I was wondering how many people would even do this correctly.

>> No.6247915

>>6247883
You were right, I forgot to add A to B

>> No.6247916

>>6247888

Quick and dirty calculations...

Force at B: 207.1 N
Force at A: 113.905 N

Basic statics.

>> No.6247929

>>6247883
I got 113.8 for A
and I messed up B, I said it was 93.1 (9.5 * 9.8) but I forgot to add A, which makes it 206.9
>>6247883
Also, this faggot who doesn't give the correct answer and only criticizes mine. What an asshole

>> No.6247930

>>6247851
A = 201.5Kg
B = 211Kg

>> No.6247932
File: 362 KB, 169x298, 1388010596510.gif [View same] [iqdb] [saucenao] [google]
6247932

>>6247930

>> No.6247939

>>6247930
>force
>in kilograms

>> No.6247941

>>6247851
F app
Applied force
good joke.

>> No.6247945

>>6247939
working with units provided, no assumptions other than pure mechanical. no integration, just logic. is the answer somehow incorrect?

>> No.6247947
File: 1.80 MB, 282x257, 1388011108998.gif [View same] [iqdb] [saucenao] [google]
6247947

>>6247929
>solving retarded problem
>spitting shit answers
>expecting praise and answers

>> No.6247949

>>6247945
200kg. Think for a second, the bar it self is 9.5Kg.
Does this seem at all logical?

>> No.6247950

>>6247949
yes considering leverage points

>> No.6247955

>>6247950

A kilogram is a unit of mass. A Newton is a unit of force. We are dealing with forces here.

>> No.6247958

Either you guys can't read, or are doing this for fun.

>> No.6247959

>>6247955
a kilogram is a unit of weight
a newton is a unit of mass

>> No.6247956

A=113.8N
B=206.9N

>> No.6247960

>>6247955
kgf exists you know

>> No.6247961

>>6247888
>9.81, I really didn't think I would have to specify this
No units. No wonder you can't do this shit on your own, you can't into basic physics. You deserve to fail.

>> No.6247962

>>6247959

Le trole face

>>6247960

Yes, but that's not what unit the guy answered with. He specified his answer in kg which is objectively wrong.

>> No.6247963

>>6247961
ah... the assumption I did not make... G = 9.81 m/s2

>> No.6247964

>>6247963
it's g, not G

>> No.6247967

>>6247961
Still under the pretense that this is somebody's homework, lol...
Make it too specific faggots cry about HOMEWORK,make it "surely this is common sense", and people like you cry.
ehh mehh

>> No.6247972

>>6247956
Solution:
-A*0.45 + (9.5*9.8)*0.55 = 0 (Pivot at B)
A = 113.8

-A + B - (9.5*9.8) = 0
B = 206.9

>> No.6247974

>>6247972
how can A + (weight of bar) not equal B ?

>> No.6247977

>>6247974
it does
>-A + B - (9.5*9.8) = 0

>> No.6247978

>>6247974
>>6247977
>-A*0.45 + (9.5*9.8)*0.55 = 0 (Pivot at B)
that's torque

>> No.6247979

I cannot believe this thread is happening.

>> No.6247981

>>6247979
neither can I, but oh well...

>> No.6247983

>>6247979
>>6247981

First day on /sci/ I take it?

>> No.6247982
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6247982

>>6247979
Really? How come?

>> No.6247986

>>6247978
A=1978N
B=2070N
>I understand torque. and lever arm distance
45cm vs 2000cm total length

>> No.6247987

>>6247983
nope, I just can't believe I actually answered OP...

>> No.6247989

>>6247986
then why??
>how can A + (weight of bar) not equal B ?

>> No.6247991

>>6247986

>2000cm
>20 meters

Confirmed for troll.

>> No.6247993

>>6247989
cumulative rounding errors

>> No.6247995

>>6247991
my bad

>> No.6247997

>>6247993
What?
oh, alright I understand why you asked that now.
my equation was ok, it was the answers which were ...

>> No.6248002

>>6247955
>A kilogram is a unit of mass. A Newton is a unit of force. We are dealing with forces here.
-correction-
>A kilogram is a unit of mass. A Newton is a unit of force. We are dealing with retards here.

>> No.6247999

>>6247997
I use 9.8m/s2 not 9.81 or w/e

>> No.6248007

>>6248002
my mistake. weight and mass are equivalent? or does that not depend on the environment? I made a mistake and slipped a decimal and worked the calcs with a 20 meter bar instead of a two meter bar.

>> No.6248013

The answer for A is 29 darth vaders and B is a Luke skywalker

>> No.6248021

>>6248007
>wight and mass are equivalent
No, weight is a force, mass is not.

W = m * g

>> No.6248024

>>6248021
But g is constant

>> No.6248029

>>6248024
>g is constant
g = G*m2/r^2

>> No.6248039

You put 21 newtons on A and ask B nicely to just stay where it is and then you have BALANCE.

That is what I say but I just don't know anything I'm on this board randumly and many of you fags have some crazy numbers so why am I wrong?

>> No.6248051

>>6248039
Look at the problem again. You clearly misunderstood the question.

>> No.6248073

>>6247851

I get 204.402N, taking g to be 9.78

>> No.6248078

>>6248073

I read the question incorrectly, I think. You have to apply this amount of force to A and you must apply 204.402+(9.5*2*9.78) to B to simply support the weight of the bar combined with the downwards force. I got my initial answer assuming B was a fixed point around which I took moments.

>> No.6248084

>>6248078
Answer 389,82N is quite off.
Your second idea is correct but your A is off in that case.

>> No.6248089

0 for each, it won't rotate with no force on either point, it'll just fall to the ground in which case it will still be parallel to the ground.

>> No.6248096

>>6248084

You sure? Pushing up with 390N (CBA for decimals right now) and down with 204N?

The force clockwise around B is going to be 1.55^2 * 9.5 * 9.78, isn't it? This means you need to push down at A with just as much force to keep it steady and then combine this with the downwards force of the bar due to gravity and mass (2*9.5*9,78) which gives my last answer.

>> No.6248097

>>6248089
A pllllluss....for Autism.

>> No.6248103

>>6248097
sorry you didn't like a simple answer to a simple problem

>> No.6248112

It's impossible to get it parallel unless Young's modulus is infinite. The rod would bend otherwise. Y'all are a bunch of mo-rons.

>> No.6248119

>>6248096
I am 100% sure that 390N is wrong.
While you are right about the weight of the bar being added to A.
Your A is likely wrong.

>>6248103
Oh cheer up, you do get a smile out of me for paying attention to the wording of the problem, and finding a "loop hole".

Your answer is miles better than people who whine about homework.

>> No.6248120

>>6248112

Don't be a dick, it's assumed for questions like this that the rod does not bend.

>> No.6248129

>>6248119

I think 390N might be wrong, yeah... You have to push down at A with either 496N* of force or 223.22N* of force and then push up at B with this +185.82N of force, which comes out to be at least 400N each time.


* - (223.22/0.45=496)

>> No.6248147

>>6248129
9.81*9.5kg=93,195N the weight of the bar.
and B should be around 215N.

>> No.6248151

>>6248120
>Asking people not to be a dick
>On /sci/

Hahaha! that's the best laugh I've had today.

>> No.6248162

A should be 113.905 N downwards, with B being 207.1 N upwards.

>> No.6248170 [DELETED] 

>>6248120
Uhh yes it would. Since the system needs to be in equilibrium to stay parallel to the ground, the member would rotate at point A because of the weight of the rod at the centroid which is in the middle.

Do you even statics bro?

>> No.6248176

>>6248147

The bar is 2M long, so you need to multiply by 2 and also I'm taking G as 9.78 not 9.81.

>> No.6248181

It's winter break retards. Who has homework over break?

>> No.6248184 [DELETED] 

Uhh yes it would. Since the system needs to be in equilibrium to stay parallel to the ground, the member would rotate at point A because of the weight of the rod at the centroid which is in the middle. Since two forces are given to counteract this moment, B should be greater than A with B being 207N upwards and A being 114N downwards.

Do you even statics bro?

>> No.6248187

>>6248120
Uhh yes it would. Since the system needs to be in equilibrium to stay parallel to the ground, the member would rotate at point A because of the weight of the rod at the centroid which is in the middle. Since two forces are given to counteract this moment, B should be greater than A with B being 207N upwards and A being 114N downwards.

Do you even statics bro?

>> No.6248197

>>6247967
But what's the point of discussing a basic statics problem?
>>6248181
Intersession, HS students if your teacher was a dick like mine was.

>> No.6248199

>>6248176
Ok, how about this.

Which weights more, 10kg bar that's 2m long
Or 10kg bar that's 10m long?
(assuming both are balanced equally at the center)
Think about that for a bit.

>> No.6248201

>>6248120
I don't know what kind of backwoods physics classes you've had, but it's not "go on what you think" as assumptions. The assumptions are defined by the professor/teacher on the exam or in the book, otherwise you're lacking a metric to asses the students' grasp on the subject.

>> No.6248218

>>6248181
Finally somebody with common sense.

>>6248197
I am going to say something really obvious: People are different. For you there might not be any reason, you might not gain any insight or a laugh from this threat. Others might.
I imagine some guy might learn something new, some gets to feel good about himself being superior, somebody enjoys a laugh from this.
Do I really need to go on?

>>6248201
Beep boop. Am I a human yet?
But seriously, if the information is not specified then it's not relevant.

It's like the gravity. If it's not specified then it's only sane to assume earths gravity.
If it's not specified that the bar bends, it's only sane to assume it's implied it doesn't.

Personally if the guy want's to take a more complicated look at it I am all for it.

>> No.6248228

>>6248181

1. Highschoolers
2. Grad students taking a year-long sequence

>> No.6248229

>>6248218
So pretty much you DID have a weak physics program, likely algebra based. If the OP were looking for better understanding then there are much better ways to address the question. Asking a bunch of engineers, physics and maths students "Are you smart enough to [do a really basic statics problem]?" doesn't really support your theory given the problem's simplicity.

>> No.6248246

>>6247851
>revised answer
A = 51.2N
B = 144.3N

>> No.6248252
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6248252

>>6248229
> Asking a bunch of engineers, physics and maths students.
Please if you would be any where near the importance you try to put on you would not be on 4chan.

>but muh
>I am important
>and smart
>and rich
>and popular
>and 12 inch dick
>still comes to 4chan

>> No.6248260

>>6248252
not the same guy but stop projecting your failure on 4chan.

>> No.6248261

>>6248246
I keeps farking it up...

>> No.6248274
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6248274

>>6248260
>s-s-stop calling me a failure.
Relax dude, I am saying the guy is not as important as he thinks he is.

>> No.6248295

>>6248274
By saying that nobody important comes to a popular internet site? Simply because someone questions your motives for asking an easy statics question?

>> No.6248603

A=0
B=0

>> No.6248643

>>6248603
B=D

>> No.6248644

>>6248643
8=D

>> No.6248646

>>6248644
8=D ( . ( . )

>> No.6248647

>>6248646
8=D (. ( . )\__/ / /

>> No.6248649

>>6248647
8=D ( (0) )-----(. )\ |

>> No.6248866

>>6248151

>asking

>> No.6248869

>>6248199

Sorry, yeah. I get it now. But the 10M bar gives more leverage than the 2M bar with its own weight. I see my mistake though, but hopefully you know how I made it.

>> No.6249081
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6249081

This whole thread...

oO'

Guys, wake up. Or post on /b/.

Seriously. Are you all drunk after xmas?

>> No.6249082

>>6247851
around 7.5 since you are applying force at the end of a bar, whereas load is applied to the bar the same distance in the other direction
Since its not homework..

>> No.6249087

>>6247964
shut the fuck up

>> No.6249095

>>6249082
this is in kilogram force though...surely you can convert...

convert 9.5 kgf for B (didn't notice this part)

>> No.6249143
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6249143

I maed you a pic, guyses

>> No.6249376

>>6249143
>>6249143
The mass is evenly distributed across the pole(at least thats my assumption)

I got 73.5 N for A, 93.1N for B initially
but then you have to correct for added force so the fulcrum can actually support it
So
A:73.5
B:144.31
A:73.5
B:
The kg

>> No.6249641

>mass is evenly distributed

Of course, but that doesn't prevent you from using a functionally equivalent model to simplify the calculation.

>> No.6249690

>>6247851
Yes.