Topic: [SOLVED] Skill Testing Math Question -- 0.08 BTC Reward (Read 2024 times)

As ndnhc pointed out, and as I already said in my answer, I gave it in mass equivalent.
What do I mean by mass equivalent?

The weight is 826.59 N, but it is the same weight of an object with mass of 84,289.46 grams on the surface of the earth.
OP asked for it in grams, so I gave it in mass equivalent.

Read my answer, it is different from lili's answer, but straightens out a lot of things he said, better explaining them.
He has a valid reason for being unable to explain it too, as English is not his first language either.

btw, that is already accounted for here:


I just corrected that here:



The question clearly states:

i want to reclamation

From your question, you are looking for weight in grams.
in physics weight are united with Newton, not in grams. but in real world sometimes people call mass as weight.

   Quote from: lili song on July 24, 2015, 08:00:46 AM
                      Centripetal_force 1      =  centripetal_force 2
   84,000 g * (464 m/2)^2 / 6,371,000 m = mass * (463.2 m/s)^2 / 6,371,000 m

   mass = 84,290.4 g

and u claimed this answer as the winner. So the answer you are looking is mass not weight.

from this https://en.wikipedia.org/wiki/Weight is the description of weight physics
and this https://en.wikipedia.org/wiki/Mass is the description of mass in physics

if you are reading it carefully, in paragraph 2 of description of mass you will read  "An object on the Moon would weigh less than it would on Earth because of the lower gravity, but it would still have the same mass".
so whenever you are, whatever the velocity or radius of the planet
your mass will still same, but your weight will change.

and I want to straighten our concept about centripetal force.

from lili song answer centripetal force 1 = centripetal force 2.
This is completely wrong! As far as i know centripetal force change as the related variable change.
Sorry, lili, i did not mean to blame you.
this for the reference of the centripetal force description http://www.regentsprep.org/regents/physics/phys06/bcentrif/default.htm

So, the answer should still same mass(weight) 84,000 grams

Yup, you owe me one for proving you right

And notbatman, shoot me a PM the next time you're hosting this sort of stuff.
This was fun, and the free BTC for a few minutes of work was more fun

Woah  I can't believe it that I'm the winner
Thanks notbatman  and thanks for jambola2 for clarification (since english is not my mother tongue, I can't argument just like you did. )

I was wonder why YouTube was suggesting me the likes of Saudi Cleric Was Right: USA Faked Moon Landing - Coriolis Effect Fraud lately. It's because I commented on this thread. Bad, notbatman! 

Don't think this proves that the Earth is a spinning globe, it doesn't. It does however prove that I'm somewhat of a massive fool for just assuming the centripetal force would be a large value. 

NASA and the rest of the establishment are a den of vipers. Their eggheads have however defiantly crunched all the numbers. I won't make the same mistake twice. Math is the only science you can be 100% sure of the results and I'm going to find a hole in their global conspiracy.

The Earth is flat!

Yes.

'lili song' is the winner! (19jD5PfF5TqeF5xJWa5US2rM7GHVr5hdX) <-- 0.07 BTC

'jambola2' is the runner up. (1FRkoJDy8CwZ84RSeMs2tCEKBdVfHu32Ra) <-- 0.01 BTC

I decided not to be a cheap ass and reward the entire 0.08 BTC but, lili song's works sucks so jamola2 gets 0.01 BTC of her reward. Technically lili song posted while the reward was 0.01 BTC so consider yourself lucky.

Lilisong answer answer is correct?

It's 4567,85 g

its too hard  

84000*464^2/6,371,000

2838.622 G

Best attempt yet... but, I need some time to go over it and some sleep. If I can't poke any holes in it I'll send the 0.08 BTC.

EDIT:

Reviewing the other posts it looks like 'lili song' (19jD5PfF5TqeF5xJWa5US2rM7GHVr5hdX) may have beaten you to it especially with your margin of error...


Oh, my precious Bitcoins, this isn't looking good for me. 'lili song' did however post while the reward was 0.01 BTC.

I'm still going over the numbers...

Reduction in weight = Change in centripetal force = m(V^2)/r - m(v^2)/r =  84(464^2 - 0.8^2)/6,371,000 = 2.83861407

However, since centripetal force is in Newtons, this is in Newtons.
Converting it to mass equivalent with the number you gave (1 newton = 101.971621 grams)

2.83861407 Newtons * 101.971621 Grams per newton = 289.458078111 Grams heavier

Wait what really? So less?

Let's look at the equation of centripetal force again.
Let's calculate the total centripetal force for any person

Mass in kg * (velocity)^2 / Radius
84 KG * 464 * 464  / 6,371,000
The thing you notice is that the radius is so large it makes the speed look extremely tiny.


Yes it is so low!
The author of that response made a mistake (464^2 - 0.8^2) =/= (463.2^2) , but was correct for the rest.

I'm not sure if you're playing a prank on the forums, but that's what happens when something is inversely proportional to the radius of something, and that radius is HUGE.

The fact that someone noted that this was consistent with NASA calculations regarding weight at the poles hints that your idea is wrong.

Leaving margin for error, I can say with certainty that the weight of the average person will be approximately 826.59 Newtons. (YES, Google it. The SI unit of weight is Newton, not mass)
Or, to use your extremely weird scale of stating weights in mass equivalent, 84,289.46 grams. Can't vouch for accuracy, may vary between 84,280 and 84,300 grams.

And here's my address: 1FRkoJDy8CwZ84RSeMs2tCEKBdVfHu32Ra

a) The SI unit for mass is the kilogram.
b) You've only attempted to calculate part of the problem.
c) Other issues with the part you've attempted.

given:  if the equatorial velocity was slowed to 0.8 m/s?
Earth's radius at the equator: 6,371,000 m
Earth's velocity at the equator: 464 m/s
Average weight of a person: 84,000 g

formula: centripetal_force = mass * velocity^2 / radius

84,000 * (464-0.8/464)^2 / 6,371,000 = 2838.60141269 newtons
2838.60141269 *101.97 =  289452.186052 grams

this is my try
i think im missing something

I've increased the reward to 0.08 BTC.

we'll apply the calculation used to answer this skill testing question to the north pole as a test of its validity later...

a) The SI unit for mass is the kilogram.
b) Where do you get '9.79' from?
c) Again, where do you get '0.00843823575' from?
d) How is the result of your calculation in grams and not newtons?
e) Many other issues.

At the Equator.


84,000 * 9.79/0.00843823575 = 97456390.6916 grams.

This is fucked up on so many levels! Does this now mean that I wasn't even close with my answer? If so, that really makes me out to look like a fool.