Can any of you hold up a 7ft 20kg barbell in the air with 1 arm?
Shit seems impossible.
>>36658591
ohaiyo kenwood-san
Some /sci/ freak calculate pls how big of a dumbell would that equal to.
I will go and ask sci.
I went to Kenya and a test of strength for the tribe was to lift a spear up similar to how you're saying. From what I remember they were of similar weight, maybe a little shorter. And they did it just fine.
>>36659038
>20kg spear
lol
>>36659084
Oh shit I forgot to convert. Nvm. It was years ago anyway.
>>36659038
>lying on the internet
Anon why?????
It would be like holding a 120 lb barbell but your forearms would also have to apply a 157.5 ft*lb torque to you hand.
>>36659105
See
>>36659103
I'm just dumb.
>>36659141
*dumbbell
nobody can do that, no
>>36659141
Tyvm.
>>36658913
>>36659009
Arm length is about 2 foot.
2 ft * X = (3,5 ft + 2 ft) * 20kg
X = 55 kg
Holding a BB is also harder because of the torque in your wrist.
>>36659141
Doesn't that 157.5 ft*lb torque make that 120 lbs figure much more? Im a dumb cunt when it comes to math, is there anyway to figure out how much that torque theoretically adds in terms of how heavy it is?
Does my question even make sense?
>>36659226
The 120 lbs is what your shoulder would feel if you were holding a dumbbell in your hand. Since the center of mass of the barbell isnt in your hand your wrist has to apply a torque to keep the bar straight.
>>36659321
Im not understanding.
I can hold a 120lbs dumbell but I can't hold up a 20kg barbell.
>That's how I into pyramid head mode.
Jk it was cardboard and I'm still jack dyellington
>>36659354
Open a door by pushing on the side with the handle and you can probably do it with your pinky. Close the door then try to open it be pushing near the hinge. Same door, same movement different tourqe. Get it now?
>>36659212
>arm length is 2 feet
Lmao what?! I mean I'm tall so mines above average but who the fuck has a 2 foot arm?
>>36659431
Mine's definitely at least two feet
https://www.youtube.com/watch?v=_CntG1pXfPI
Why are you guys just multiplying by feet?
I don't know how to work the equivalent weight out but I'm fairly sure just multiplying the weight by it's distance from the body is nonsense.
If multiplying by feet works then it will not work for any other unit of measurement, meaning that feet would be factored into something already in place, which I highly doubt.
Also, resisting the torque on your hand would be the first thing to fail.
>>36659481
Actually, the weight doesn't even change, that in itself is nonsense. The rotational force on the hand is the only difference.
>>36659141
>he assumes the weight of the bar is evenly distributed along its length
>>36659481
torque is in ft*lb. The torque on your shoulder would be 250 ft*lb which is the same as holding a 120lb barbell armslength.
>>36659710
it's not but the bar is symetrical so the center of mass is in the middle and you can treat it like a point mass
>>36659710
>assumes you need to take quantum fluctuations into account to solve a Newtonian physics problem
>>36659466
That was... relaxing to watch.
>>36659809
>implying weight distribution is a quantum fluctuation and the weight of a nonreacting solid is inconsistent
>>36659141
Can't for the life of me figure out where the 12 in 25/12 comes from
>>36659431
most people have an armspan that is pretty close to their height, and very few people are 2 feet wide across their shoulders (24in). your arms are probably about 2 feet long, he's right
>>36659354
>using lbs and kg in the same post
REEEEEEEEEEEE
I touched my nose with a 12 pound sledge before and brought it up.
A barbell I'm guessing is straight up impossible though
>>36659481
>>36659141
what we need to is find the rotational force required to keep the barbell up and compare it to the rotational force required to hold a dumbbell up
however its been years since i did physics so im not going to bother with that shit
http://www.dummies.com/how-to/content/how-to-calculate-rotational-work.html
>>36660152
Huh. I am average height, and I assumed my arm was much longer, but I used a cloth measuring tape, and from tip of the shoulder to the wrist bone was 20", and 27" to the tip of my finger.
>>36660088
12 inches in a foot
>>36660465
>/sci/
>go into thread
>should be 10 replies and problem solved
>forgot its 4chan and we can't even count to 5
I will come back tomorrow when it hits 300+ posts of shitposting. Never change.
I see /fit/ is full of nerds
>>36659724
rotational inertia is based around the square of the distance to the pivot
>>36659141
Statics bro!
>>36658591
What is leverage?
>>36658591
No way, I barely managed one of those bodypump bars
I do this with broomsticks all the time
Shits hard as fuck.
Try getting a barbell and putting a plate or two on each end (use clips for this, tard) and try doing a farmer's walk with it using only one hand
It's hard as fuck. Itll feel like your hand is never quite in the middle and that shit will rotate in every direction like my dick following that hot bitch around her insane machine circuit
Can't even imagine OPs shit
>>36666895
>like my dick following that hot bitch around her insane machine circuit
kek
>>36659141
that's incorrect, becase the weight weighs with different lever the further it is from your hand. Imagine a 2 inches lever with a 45 attatched to the end. Woudl be easy enough to hold, right? What about 8 feet lever, like barbell with 45 attached to the end? Shit would be impossible to hold. But in barbell the weight is spread more or less equally.
I think we need to use some integrals to get correct results
>>36667044
I know enough to know this guy is right on but not enough to have any fucking clue where to begin. Fuck math in its condescending ass.
>>36658591
Someone do the correct math im seriously interested.
>>36663935
yes, but we're not talking about rotational inertia, we're talking about the torque applied to hold the bar parallel to the ground, which can be calculated using the assumption that the mass is at a point in the centre of the bar
