# Ekene Franklin's messageboard.

Feel free to discuss anything here with me friends! We're here to help each other!

Note by Ekene Franklin
2 years ago

This discussion board is a place to discuss our Daily Challenges and the math and science related to those challenges. Explanations are more than just a solution — they should explain the steps and thinking strategies that you used to obtain the solution. Comments should further the discussion of math and science.

When posting on Brilliant:

• Use the emojis to react to an explanation, whether you're congratulating a job well done , or just really confused .
• Ask specific questions about the challenge or the steps in somebody's explanation. Well-posed questions can add a lot to the discussion, but posting "I don't understand!" doesn't help anyone.
• Try to contribute something new to the discussion, whether it is an extension, generalization or other idea related to the challenge.
• Stay on topic — we're all here to learn more about math and science, not to hear about your favorite get-rich-quick scheme or current world events.

MarkdownAppears as
*italics* or _italics_ italics
**bold** or __bold__ bold
- bulleted- list
• bulleted
• list
1. numbered2. list
1. numbered
2. list
Note: you must add a full line of space before and after lists for them to show up correctly
paragraph 1paragraph 2

paragraph 1

paragraph 2

[example link](https://brilliant.org)example link
> This is a quote
This is a quote
    # I indented these lines
# 4 spaces, and now they show
# up as a code block.

print "hello world"
# I indented these lines
# 4 spaces, and now they show
# up as a code block.

print "hello world"
MathAppears as
Remember to wrap math in $$ ... $$ or $ ... $ to ensure proper formatting.
2 \times 3 $2 \times 3$
2^{34} $2^{34}$
a_{i-1} $a_{i-1}$
\frac{2}{3} $\frac{2}{3}$
\sqrt{2} $\sqrt{2}$
\sum_{i=1}^3 $\sum_{i=1}^3$
\sin \theta $\sin \theta$
\boxed{123} $\boxed{123}$

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My country's national olympiads 1st round is to be conducted tomorrow. I will most likely post all of them here for our consumption! I expect them to be pretty easy.

- 2 years ago

Ok. Thanks and also are you writing that exam.

- 2 years ago

It is actually meant for students two years older than I am, but I will give it a shot.

- 2 years ago

Oh !!!

- 2 years ago

It there a minimum age requirement to be eligible to write your country's olympiads?

- 2 years ago

Yes, I think it is 13 or 14. People from class 8 or 9 onwards can write the exam.

- 2 years ago

Are you also writing the olympiads soon?

- 2 years ago

No. At present I am not interested. The main goal of student student studying in class 11 and 12 in India is to get into IIT (Indian Institute Of Technology)

- 2 years ago

Oh, so that is what JEE and IIT are all about. I hope you get into it seamlessly. But say, do you hope to write olympiads in the future?

- 2 years ago

Yes. I may.

- 2 years ago

This is a marvelous secret and I benefited a lot from this. If you want to write any question for the problems of the week the better option is to write a physics problem rather than maths. Out of 5 problems 3 are allotted for maths and 2 for science. In the maths category there will be a much competition from many users. But in the science category there are only 4 competitors namely Rohit Gupta, Pranshu Gaba, and two staff members Blake Farrow, Danielle Scarano. So, I posted some good physics problems and 3 of them are featured now. But I won't force you to post only physics problems then there will be much competition for science. If you have good problems in maths you can post them (as 3 of my maths problems are also featured although I say that I am basically a physics man).

- 1 year, 12 months ago

Where is the show full site option??(from ur mt. Everest Q discussion)

- 1 year, 11 months ago

It will be in the main option bar. It is the place where you can find links like "profile", "stats", "search", etc. The "view" full site option will be present there.

- 1 year, 11 months ago

Main option bar : Those 3 lines on left corner?? Or in the stats section of taskbar?

- 1 year, 11 months ago

The three line aside the option "Premium"

- 1 year, 11 months ago

Oh so this is on website. Can this be done in app?

- 1 year, 11 months ago

Ohh !! You are doing in the app. Sorry, I don't know whether this is possible in app or not. But can't you find any option like this. in the screenshot.

- 1 year, 11 months ago

No :-( how can I send screenshot on this chat?

- 1 year, 11 months ago

You have to copy the link of the picture and paste it here.

- 1 year, 11 months ago

K thnx a lot for helping, and sorry for disturbing..

- 1 year, 11 months ago

It's OK. No problem. I went to brilliant only once in the mobile app so I am not much aware of the options present in it.

- 1 year, 11 months ago

Mauj Rajpal, from which part of India are you from.

- 1 year, 11 months ago

Delhi ;-) and u??

- 1 year, 11 months ago

- 1 year, 11 months ago

Oh nice. From where do you put your problems in sets(source) and how do you have sets of other people in yours??

- 1 year, 11 months ago

In every set there will be a option at the bottom called "save". If you click that, that particular set will be saved into your sets. Some of my problems are original whereas some other are completely taken from books or the problems and the remaining are the problems which I have taken from books and modified them.

- 1 year, 11 months ago

Can you suggest me some of your book(especially maths)

- 1 year, 11 months ago

It's our college material. It is a collection of all good problems from various books.

- 1 year, 11 months ago

Here is the screenshot of where is it present. Can you find it now ?

- 1 year, 11 months ago

Is this screenshot from app?

- 1 year, 11 months ago

No. It is from from the main website.

- 1 year, 11 months ago

How do you send questions to them to select for weekly problem??Do they themselves select from your sets?

- 1 year, 11 months ago

No. Only staff will select the problems of the week. In general, the notification will be as if I have written the problem of the week.

- 1 year, 11 months ago

They themselves select it by seeing your sets or you send them via some forum and then they choose one of the all sent questions??

- 1 year, 11 months ago

The community members write problems and post them to community and the staff selects the best 15 questions among all the problems and they will feature them as problems of the week. There is no forum involved in this process.

- 1 year, 11 months ago

I personally think Brilliant should include a biology and biochemistry section. What do you think?

- 1 year, 10 months ago

Yes.

- 1 year, 10 months ago

Before brilliant used to have biology. But recently when the staff updated brilliant they removed biology topic due to lack of problems in that category.

- 1 year, 10 months ago

Actually I asked them to remove it, because the biology problems could not be seen in the community page. You can see Calvin Lin's messageboard.

- 1 year, 10 months ago

@X X Calvin Lin's message board is currently unavailable. I searched for the website for a long time but in vain. Maybe he have locked it.

- 1 year, 10 months ago

Really? Here is the link. It's still available.

- 1 year, 10 months ago

@X X But last time when I went it was locked

- 1 year, 10 months ago

yes

- 1 year, 10 months ago

Here is a link of a biology problem.

- 1 year, 10 months ago

Yes, but they cannot be found in the community page.

- 1 year, 10 months ago

@X X I know. And there is no biology when you're making a problem.

- 1 year, 10 months ago

@B D Previously there was, but they removed it.

- 1 year, 10 months ago

@X X OK

- 1 year, 10 months ago

- 1 year, 10 months ago

Hello Everyone !!! As this note has got some immense response from young students I would like to continue this further. But the problem is that this note is getting more and more comments day by day due to which the process of loading and opening any notifications is taking more time. So, on the request of @EKENE FRANKLIN any further discussion can be continued in the new note Brilliant young students messageboard

- 1 year, 10 months ago

$\text{Doubt : 1}$

If the mole fraction of a solute is changed from $\dfrac14$ to $\dfrac12$ by adding some solute in the $800~g$ of $H_2O$ solvent, then what will be the ratio of molarity of the two solutions ?

- 2 years ago

$\text{Doubt : 2}$

In the following reaction : $\large aNO_3^- + bCl^- + cH^+ \rightarrow dNO + eCl_2 + fH_2O$ find the value of $\dfrac{a^2(b + c)}{d \times f}$

- 2 years ago

Simply balance the redox equation and substitute the stoichiometric coefficients of the balanced reaction into your expression.( I would have posted a solution if only my device could type LaTeX.)

- 2 years ago

Ok. Try now after keeping it in \ (....) without spaces which will give you $...$

- 2 years ago

Did you tried it. What is the answer you got.

- 2 years ago

Yeah, I solved it. My answer is 7.

- 2 years ago

That's correct answer. Can you atleast keep the values of a,b,cd,e,f.

- 2 years ago

a=2, b=6, c=8, d=2, e=3 and f=4

- 2 years ago

Ok. Thanks i will check with mine.

- 2 years ago

$\text{Doubt : 3}$

Uncertainty in position and momentum are equal. Then what will be the Uncertainty in velocity ?

- 2 years ago

I don't think uncertainty in position and momentum are relativistically equal. However, if a non-relativistic assumption is to be made, then from Heisenberg's, and taking p=mv, then uncertainty in velocity>=(h/2pi)X(1/(uncertainty in position X mass)). Sorry for the math ambiguity. My device doesn't type LaTeX.

- 2 years ago

Yes you are correct. You got the correct answer. Regarding the latex you can keep it in \ (...\ ).

- 2 years ago

The LaTeX is not still working. It prevents me from posting some reeeeeeallly cool problems.;(

- 2 years ago

$\text{Doubt : 4}$

In $(Si_4O_{12})^{8-}$, how many $Si - O - Si$ linkages are there ?

- 2 years ago

I have an answer, but I am not totally sure it is correct. Coordination structure chemistry of silicates and silicones is my weakest point in chemistry. Perhaps I need to practise more!:)

- 2 years ago

What is the answer bro?:)

- 2 years ago

It is 4.

- 2 years ago

I was actually sure of 4 linkages, but I was not sure of one more. Thanks anyways.

- 2 years ago

It's OK.

- 2 years ago

You are a great guy, Ram.

- 2 years ago

That's my quality quantitatively speaking.

- 2 years ago

My goal in many interactions is to make them frictionless. Trivially speaking, I resist every enmity and conduct friendliness. I have even successfully transmuted people from an angry ground state, to a happy excited state!

- 2 years ago

Oh !!! That's good.

- 2 years ago

Thanks. Ask if you want more!

- 2 years ago

Thanks guys. Keep sending problems and lets discuss!

- 2 years ago

Hi guys! For sure we all have noticed that the derivative of kinetic energy is momentum. Is there a physical explanation for this?

- 2 years ago

Quantitatively speaking, momentum is the product of mass of a body and its velocity. It is denoted by $\overline{P}$. $\large \overline{P} = m \overline{v}$ But the above definition is valid only when velocity of the body is constant. If the velocity of the body is variable we cannot use this formula and we should go by calculus. Physically speaking, momentum is the rate of change of kinetic energy with respect to its velocity. So, you ca say it as kinetic energy at that instance. Here is how we get $\overline{P} = m \overline{v}$ from kinetic energy. $K.E = \dfrac12 m (\overline{v})^2$ Now, differentiate both side with respect to velocity. We get : $\dfrac{d}{dx} K.E = \dfrac{d}{dx} \left ( \dfrac12 m (\overline{v})^2 \right )$ As, we know $\dfrac{d}{dx} K.E = \overline{P}$, we get : $\overline{P} = \dfrac12 \cdot m \cdot 2 \overline{v}$ So, we get : $\large \boxed{\color{#3D99F6} \overline{P} = m \overline{v}}$

- 2 years ago

Perfect bro!

- 2 years ago

Thanks. But what I should say you, brother or sister

- 2 years ago

I am a young boy:)

- 2 years ago

Ok

- 2 years ago

Explain the Bohr theory of atoms, combining both mathematics and physics in your explanations.

- 2 years ago

Does anyone know how to post a solution of a problem that doesn't have a posted solution yet?

- 2 years ago

If you got it correct you click the button "No solution" under Continue and write. And if you got it wrong you can't.

- 2 years ago

Thanks a lot, bro!

- 2 years ago

You are welcome!

- 2 years ago

@Mohmmad Farhan why can't you come here. I think this is a best place for a student like you. You can post your quires here.

- 2 years ago

Sorry! I am not really active these days because of exams

- 2 years ago

Ok. No problem !!!

- 2 years ago

How do I post numerical answer problems on Brilliant?

- 2 years ago

I think you have posted many problems in brilliant. However, when you are writng a question there will be two options, either Number or Multiple choice. You can select whatever you wish.

- 2 years ago

Gearing up for today's 1st round olympiads!

- 2 years ago

Good luck!

- 2 years ago

Thanks. The results will be uploaded online in about 1.5 hours. Meanwhile I am posting them here for our consumption. Solve some, post solutions and invite others to do same!

- 2 years ago

Maybe you can post them like problems.

- 2 years ago

@B D Ok.

- 2 years ago

Problem 1: A password consists of $4$ distinct digits such that their sum is $19$ and exactly two of its digits are prime, e.g. $0397$. How many possible such passwords exist?

- 2 years ago

2,3: (2,3,6,8)

2,5: (2,5,4,8)

2,7: (2,7,4,6),(2,7,1,9)

3,5: x

3,7: (3,7,1,8),(3,7,0,9)

5,7: (5,7,1,6)

There are $7\times4!=168$ possibilities

- 1 year, 12 months ago

How did you get all possibilities?

- 1 year, 12 months ago

Find the 7 possibilities one by one, then times 24

- 1 year, 12 months ago

Problem 2: What is the maximum possible area of a quadrilateral of sides $1, 4, 7, 8$?

- 2 years ago

I think we should use the concept of maxima and minima.

- 2 years ago

Perhaps you should solve it. I used the maximality condition of Bretschneider's formula. My answer was $18$.

- 2 years ago

Yes I too got like that.

- 2 years ago

What is that?

- 1 year, 11 months ago

Looks similar to:

https://brilliant.org/problems/hexagon-octagon-in-a-rectangle/?ref_id=1538063

Maybe a harder version perhaps! :D

- 1 year, 11 months ago

Problem 3: $20$ lines are drawn in a plane. What is the maximum number of parts into which the plane can be divided by the $20$ straight lines?

- 2 years ago

I think it is $211$

- 2 years ago

There is a trick. First, take the 20th triangular number. $\displaystyle\frac{20(20+1)}{2} = 210$ Add 1. $210+1=211$ These numbers are known as pizza numbers and are always one more than a triangular number.

P.S. @EKENE FRANKLIN did you use this method?

- 2 years ago

Great! Just what I wanted, and what I used during the examination!

- 2 years ago

Thumbs Up!

- 1 year, 12 months ago

What is the remainder when $1^{241} + 2^{241} + 3^{241} + 4^{241}$ is divided by $5$?

- 2 years ago

$0$

- 2 years ago

Of course that is the answer, but prove it.

- 2 years ago

Since the divisibility rule of 5 only concerns the last digit, we have to find the last digits of the values. $1^{124}$ is obviously 1. Since the repetition in the last digit is (for 2): 2, 4, 8, 6 then $241 \div 4 = k (\text{Remainder}1$) the first number is 2 (in this set). Apply this to the other powers. Summing the last digits, we get 10 and $10 \div 5 = k (\text{Remainder}0)$

- 2 years ago

Excellent

- 2 years ago

Great job. I did modular arithmetic during the examination.

- 2 years ago

Me too

- 1 year, 12 months ago

Problem 5: Find the general term of the sequence described by $a_n = 4a_{n - 1} - 3a_{n - 2}$ given that $a_1 = 1$ and $a_2 = 9$.

- 2 years ago

$a_n=4\times3^{n-1}-3$

- 1 year, 12 months ago

Great. This was what I got. But do you mind showing your solution so I can clarify mine?

- 1 year, 12 months ago

Solve the equation $x^2=4x-3$ and get $x=3$ or $1$. Let $b_n=3^n-1^n$.

The first few terms of $b_n$ is $2,8,26,80...$ and $b_n$ also satisfies the recursion $b_n=4b_{n-1}-3b_{n-2}$

Compare the two sequences: $a_n=\frac43b_n-\frac53=4\times3^{n-1}-3$

- 1 year, 12 months ago

@X X Not exactly what I did, but something similar. Thanks a lot. If I may ask, have you ever participated in an olympiad before, or do you hope to participate in one?

- 1 year, 12 months ago

No, I haven't. I knew few things about it, so I'm not sure about participating in one.

- 1 year, 12 months ago

@X X Ok. Thanks. By the way, I really admire your problems. They are very cool. One of my major problems here is creating problems. My original problems are too easy(you can check them out). But solving others problems(of course not those extremely hard ones) is not a big problem for me.

- 1 year, 12 months ago

@X X I think this is your first problem of the week in easy catogery.

- 1 year, 12 months ago

You're right! (Ha, ha! I'm a little jealous of you because your problems are often the first problem in the easy category, and in your contributions page, the number of people are banging up:p)

- 1 year, 12 months ago

@X X But I am not fully done. I expected that Number + Reciprocal will take me to 1 lakh (100 K) solvers. But it fell short of 7 K. But luckily this week too my question came in one of the problems of week (the first one) so it is confirmed that I will reach the milestone in one or two days.

- 1 year, 12 months ago

@X X But some of your problems came in Intermediate and Advanced catogery.

- 1 year, 12 months ago

I know. (Fewer people solves those, that is why I was so happy to see my problem as the second of the basic category)

- 1 year, 12 months ago

@X X OH !!! Your problem is featured as the second one in the problems of the week. But my first problem (Thundering Question) is the third one.

- 1 year, 12 months ago

Oh, I remember that one! (I loved that week because a lot of my solutions appeared in that week. )

- 1 year, 12 months ago

@X X Yes, Vamprie Fan Club. It is were I had my first individual century. After that, the next week I had got 150 upvotes for my question Rising Balloons and the next week is a memorable for me, as I had my first double century for the question Counting 0's.

- 1 year, 12 months ago

@X X Ram Mohith and X X, both of you are excellent problem contributors, some of the best here. I hope I can reach your level!

- 1 year, 12 months ago

@X X It's a Fact :

I have made a hatrick in June 9 - June 29 (3 weeks) as 3 of my problem continuously came in easy part of the POTW. Now again the chance has come for me. Last week and this week too two of my problems are featured. So, if luck favors next week to I can have a problem in POTW. I am thinking very hard on which question should I post the next.

- 1 year, 12 months ago

The sequel to the Mt Everest problem about pressure cookers?

- 1 year, 12 months ago

Should see about it.

- 1 year, 12 months ago

Is it released yet?

- 1 year, 12 months ago

No. Still under construction. Before that one I have two more questions, Raising Balloons - 2 and Popping balloons which are yet to be released. After these two the sequel for My. Everest vs Mt K 2 will be released.

- 1 year, 12 months ago

OH!

- 1 year, 12 months ago

How is my new problem, check it here. It is posed by B.D

- 1 year, 12 months ago

Cool video!

- 1 year, 12 months ago

@X X Yes. I liked that so much that I framed the question based on that.

- 1 year, 12 months ago

@X X Don't worry mister !!! You have the skill to post and solve tough questions (level 4 and 5).

- 1 year, 12 months ago

I made the cut for the 2nd round! I scored $76.70$ out of a maximum possible 110. Hurray!

- 2 years ago

Oh !!! Congrats.

- 2 years ago

Thanks a lot. But no one apart from us is solving the problems. I want to check my solutions and my faulty areas. Please direct the problem solving masters of Brilliant here to help me out.

- 2 years ago

If you want to direct anyone to this place just keep the symbol @ and type the name of the person. Immediately a notification will be sent to that particular user.

- 2 years ago

Hi guys !!! I want to tell you some secret. I think next week would be a week of physics. Because this week I have found six problems which have equal chances in coming to problems of the week. There are Rohit Gupta's Trick Spring Balance and Spring Balance, Pranshu Gaba's Three blocks Sliding and Relative Stuntmen Motion, Danielle Scarano's Thermographic Dog and my Mt. Everest vs Mt. Godwin Austin. I think these question will be featured definitely this week if not possible then next week.

- 2 years ago

@Calvin Lin

- 2 years ago

I think you there is some error in spelling or you have kept a gap between the symbol and name. Once check again. If it is correct then you should get it in blue color link and not just normal text.

For example you should type it as @ _ Ekene Franklin ( _ symbol means no gap) then you will get it as @EKENE FRANKLIN

- 2 years ago

It is not still working. Do I need to add something like a code or anything, or should I just type it?

- 2 years ago

You should select from the list which will appear when you type the name. Also the name should be exactly matching with that particular user even capital letters should be taken into consideration.

- 2 years ago

Which list?

- 2 years ago

Ok. If you want I will do it on behalf of you.

- 2 years ago

Of course I want! Thanks!

- 2 years ago

Tell the names of whom do you want to be called to this note.

- 2 years ago

@Calvin Lin, @Harsh Shrivastava, @Chew Seong Cheong, @Michael Mendrin, @X X, @Aniket Sanghi.

- 2 years ago

- 2 years ago

- 1 year, 10 months ago

@X X, @Michael Mendrin, @Chew-Seong Cheong, @Mohmmad Farhan,and the rest of all, Can you please participate in this message-board (as requested by Ekene Franklin)

- 2 years ago

What courses would you recommend for a 4th grader like me?

- 2 years ago

You are 4 the grade ????!!!!!

- 2 years ago

10 years old. I told you

- 1 year, 12 months ago

But, I didn't think you are 4 th grade.

- 1 year, 12 months ago

I am! REALLY

- 1 year, 12 months ago

I am going to be 5th grade

- 1 year, 11 months ago

Oh !!! Good. All the best

- 1 year, 11 months ago

Actually I am 1 year away from board exam (in 2020)

- 1 year, 11 months ago

My first trophy was in Grade 1(third)[english], Second in grade 2 (1st)[first scrabble competition] and third in grade 2(Best school player award)[first scrabble competiton]

- 1 year, 11 months ago

# BrilliantForLife

Dare you to toggle $\LaTeX$

- 2 years ago

I have a proof for the existence of infinite dimensions.

On a line (1 Dimension), a number can be represented by a point. On a grid (2 Dimensions), an intersection is represented for the data in a cell. In a cube (3 Dimensions), data can still be represented on a point (where straight lines intersect). Following this pattern, there are infinite dimensions (because there are $\aleph_0$ numbers).

- 2 years ago

Problem 6: Find all primes which are the sum of two primes and difference of two primes.

- 2 years ago

5=7-2=3+2,this is the only possibility.

- 1 year, 12 months ago

Exactly. Just what I did during the exam, using the logic that if a prime satisfies those conditions, then the only even prime, 2 must be in the sum and difference.

- 1 year, 12 months ago

Problem 7: Simplify $S = (cot 10^\circ - 3\sqrt{3})(cosec 20^\circ + 2cot 20^\circ)$

- 2 years ago

Why are you keeping square brackets. For square root you just need to keep flower brackets.

- 2 years ago

For trigonometric functions, logarithms, limts, etc you must keep a slash before them. Like \cot will be as $\cot$ and \log will be as $\log$.

- 1 year, 12 months ago

Problem 8: A unit square is completely covered by $3$ identical circles. Find the smallest possible diameter of the circles.

- 1 year, 12 months ago

Problem 9: How many $6$ digit numbers can be formed using only odd digits?

- 1 year, 12 months ago

Is it 5^6?

- 1 year, 12 months ago

Correct. Nice stuff. What did you do?

- 1 year, 12 months ago

There are 1,3,5,7,9 five odd digits. There are six digits, each digit has 5 possibilities, so there are 5^6 possibilities

- 1 year, 12 months ago

@X X Bro, u are amazing

- 1 year, 12 months ago

DO YOU SERIOUSLY HAVE TO GIVE ME 46 NOTIFICATIONS OVERNIGHT!

- 1 year, 12 months ago

Is that bad, Mohmmad? I am usually on Brilliant throughout the night.

- 1 year, 12 months ago

I HAVE EXAMS

- 1 year, 12 months ago

I see. But you can use Brilliant to prepare.

- 1 year, 12 months ago

English EXAMS

- 1 year, 12 months ago

Farhat, from which part of India are were from ?

- 1 year, 12 months ago

Andhra Pradesh, From Khammam

- 1 year, 12 months ago

I am also from Andhra Pradesh. From Visakhapatnam.

- 1 year, 12 months ago

I am Telugu. You are Telugu right because you are from Andhra Pradesh right?

- 1 year, 12 months ago

Yes. I am born in Visakhapatnam.

- 1 year, 12 months ago

Don't call me Mohmmad

- 1 year, 12 months ago

Sorry, but why?

- 1 year, 12 months ago

See, My brother's name is Farhan but I am Farhat. And Mohmmad is his surname and Mohammad is my surname. (Stupid Passport errors)

- 1 year, 12 months ago

- 1 year, 12 months ago

YES! FINALLY!

- 1 year, 12 months ago

You can change your name in the account settings

- 1 year, 12 months ago

@X X I don't bother

- 1 year, 12 months ago

Did you know that :

$1 + \omega = \omega \ but \ \omega + 1 \neq \omega$

Freakin' cool right?

P.S. $\displaystyle \omega \ is \ the \ second \ lowest \ level \ of \ \infty \ after \ \aleph_0$

- 1 year, 12 months ago

Finally I reached it. I have reached 1 lakh (100 k) solvers in 91 problems.

- 1 year, 12 months ago

Congratulations!

- 1 year, 12 months ago

Do you know the minimum people to reach?

- 1 year, 11 months ago

I didn't get your point !!! Are you asking about minimum people required to get contribution page.

- 1 year, 11 months ago

Yes he is.

- 1 year, 11 months ago

@X X I think you must minimum have 5K people reached. But the main parameter I think is that the contribution page is mostly obtained either by up votes or by solvers to the question (more than 1K). When I got my contribution page I have around 120 upvotes, around 300 solvers, around 30 views for my notes.

- 1 year, 11 months ago

OK. Thanks!

- 1 year, 11 months ago

@X X @X X, I want your help. I am trying to write a new problem but I got struck up at one point. Here is my doubt :

Suppose lets say a man jumps from a building with initial velocity $u$. After $x$ seconds another man freely falls from the same building and from the same height. Now, we can say that the displacement of both the man's are equal as they both reach the ground simultaneously after they jump from same point, so we can equate their distances. Here is what I did : $ut + \dfrac12 gt^2 = \dfrac12 g(t - x)^2$ where $t$ is the time taken by the first person to reach the ground. The main part of my doubt is that whether we should write the time taken by second person as $(t - x)$ or $(t + x)$.

- 1 year, 11 months ago

I'm not good at physics, though. I think the time taken by the second person should be as same as the first one, maybe?

- 1 year, 11 months ago

@X X What I think is that as the second person jumps after $x$ seconds his time period will be $(t - x)$ seconds. Let's ask it to staff.

- 1 year, 11 months ago

So, are you caculating " when the first man fell to the ground, what is the distance between the two man"?

- 1 year, 11 months ago

@X X No. Both man reach the ground simultaneously so can we write the equation as in my before comment in which we equate displacements.

- 1 year, 11 months ago

Oh! Sorry, I misread the problem.

- 1 year, 11 months ago

Yes, I too think the time taken by the second person is $t-x$

- 1 year, 11 months ago

It should be t+x as he is free falling and the previous one jumped with velocity u

- 1 year, 11 months ago

DO or DIE

You are lost in a forest on a cold midnight day. The temperature is quite low and it is bitter cold. Now you have only two chances :

• You should lie on the ground and should shrink your body like a tight pack.

• Go and stay in the water in a pond nearby.

There not much time left. Take your decision before cold kills you. So, what wold you choose ?

- 1 year, 12 months ago

First option.

- 1 year, 12 months ago

But the second one is the correct choice you have to make.

- 1 year, 11 months ago

Why? Because of anomaly in expansion and contraction of water.?

- 1 year, 11 months ago

And also due to the high specific heat capacity of water. This question is a slight modification of air currents (due to which it is cool during the day and warm during night near coastal areas) and I am going to post this very soon.

- 1 year, 11 months ago

I thought as much.

- 1 year, 11 months ago