I heard this problem on a TV show, where Girl_A asks Girl_B this question. Girl_A was threatened by Girl_B and wanted to ask her a ‘tough’ question to make her look bad (it worked, Girl_B wasn’t able to answer it) I found this odd because while watching the show, I had the answer in my head almost instantly.

A few weeks back a friend was visiting me, and on a long (boring) road trip, just for the heck of it, I decided to ask my friend the same question. Here goes:

“I take a string, and wrap it around the earth at the equator. Then, once I’ve done that, I add one meter to the string. What will be the gap between the surface of the earth and the string?” I then promoted the assumption that for simplicity, assume the earth is a sphere.

You’re right! the answer is 0.15 meters. Unfortunately, my friend did not reach the same conclusion. I then tried to explain how to get to that answer, but was unable to do so. She was just not able to comprehend that this value (0.15) is independent of the radius of the sphere and we decided to ‘agree to disagree’.

The whole incident gave me deep insight into how some other people think and function. There’s a spatial way of thinking (something as big as the earth, how will 1 meter of anything affect it) and a factual way of thinking (what’s the formula for circumference, and how will it change if ‘r’ radius changes). I would imagine most people think about the formula, but it turns out, most people think spatially.

I knew this was the case when I wasn’t asked about the formula for circumference, but rather the radius of the earth!
 Anyway, here’s how to think about the problem and get the answer in a few seconds:

Start with understanding that wrapping a string around a sphere effectively makes it a circle (you can also get to this from the assumption/hint promoted at the end of the question). Then (if you don’t know it already –you should– the formula of circumference and transform the verbal problem and the two stages of it into mathematical equations.

c = 2πr -> (1)
c+1 = 2π(r+x) -> (2)

(1) represents the act of wrapping a string along the equator

(2) represents the the act of adding 1 (m) to the string

The hard part is done. All you need to do now is solve for x!
So,
(1) ÷ (2)

c / (c+1) =  (2πr) / (2π(r+x))
c+1 / c = (r+x) / r
1 / c = x / r
c = r / x
2πr = r / x
x = 1 / 2π = 0.15

hence, x = 0.15 independent of radius.

Simple, right? You don’t need to know the radius of the earth (who remembers the exact value anyway?) because it doesn’t matter!

Cheers, and Happy New Year!

just got my surface rt, and touch cover. loving it so far 🙂 feels nice to have it be a tablet when I need to or a proper desktop with office other times. the touch keyboard definitely needs some getting used to though, getting better as I type this.

 

is this the ipad killer?

The windows command prompt – It’s a lot more powerful than you think it is. I always thought the Linux shell was awesome, but after having used the windows ‘cmd’ for a while now, I think it has pretty much everything the Linux BASH did and I don’t miss the Linux one. Oh, and there’s also powershell. Checkmate BASH.

Power shell is way too awesome to even begin talking about here. So, I won’t. I will however, talk about how I’ve customized my windows cmd prompt.

1. Get some basic tools.
Console2 and Sysinternals Suite. Console2 is a tabbed console window, and it’s pretty awesome. Open source too. Sysinternals Suite is a collection of invaluable tools. Must have.

2. Create a launcher that allows you to run a script.
This is easy, create a new shortcut with this target: cmd /K “c:\setenv.cmd”. This can be done by adding a tab to Console2, and setting that in the “Shell” textbox.

3. Define the “c:\setenv.cmd” file for you purposes.
Mine does the following:

    – Set the prompt format -> prompt $P$_$G$S (I like the entire path on one line, so it’s easy to copy and read – but you can do your own thing)
    – Load of my favorite macros -> doskey /macrofile=C:\macros
    – Set some path variables -> set PATH=%PATH% (I also included the folder where I unpacked the Sysinternals Suite)

4. Define the macrofile
This is a list of macros that you define in the file you point to above (c:\macros) and I believe this file keeps evolving over time, you add stuff as you see fit, or when you learn about something new. Very helpful.

5. Change the colors/font
I use one of these fonts, designed specifically for the console, and I honestly prefer a light text on a dark background, as it’s just so much easier on the eyes.

Imagevivek

Make M3U

31.Dec.2010

This program allows you to drag and drop a folder onto it, and it will generate a playlist (m3U) file in that directory with all the .mp3, .aac, and .mp4 files in that directory. Adding more formats is really easy, so let me know what else you guys want…

Download Here (203 KB)

Wake On Lan

31.Dec.2010

Wake On Lan v0.0.1

This program sends a WOL “magic packet” to the desired NIC. If everything is setup right on the target. It will boot up.

You will need the MAC address of the NIC you want to send the packet to.

Usage: wol.exe <MAC Address>

Download Here (2.4 KB)

I use fedora from time to time. Listen to music, watch some videos, try some new programs that I think are cool. My primary OS is windows though…

I just use linux when im bored with the usual windows 7 and want to try something different.

It’s refreshing, i like how clean it is and i often continue to use it for a few days before I go back to windows, and that really makes me appreciate it more 😉

anyway, so there are a few things that i find annoying about linux. i feel like its another vista. they ask for the root password for every small change. i find it annoying.

the two most common ones are:

1. changing the CPU scaling policy. when my laptop is plugged in, i’d rather it use all the CPU it can get. to change this i need the root password. annoying.

2. mounting a NTFS drive. i have all my music on the NTFS drive i keep for windows, to mount it, it needs the root password.

luckily its easy to fix it 🙂

Here’s how:

The directory contains the policy files for the above actions, you can edit it them to reflect the changes.

/usr/share/polkit-1/actions/

for 1, and 2 above you will need to edit the files ‘org.gnome.cpufreqselector.policy’ and ‘org.freedesktop.udisks.policy’

scroll down to find this part and change the <allow_active> tag from ‘auth_admin_keep’ to ‘yes’

vivek

HTC Tattoo

03.Jan.2010

Posting this from the WordPress client for my phone.

Used this phone for about 2 weeks now and I love it! While buying it, I was on the fence between this and the HTC Touch2, but I’m glad I picked this over the window mobile.

HTC isn’t too popular yet, but I have no doubt that HTC is the next big thing. They are getting it right… let’s see if I’m right 😉 I should review this post in a year or two.

Apart from this, just a week left at home. Dreading the next few months. Oh well, here we go again 🙂

I seem to have a lot of time on my hands off late (more on that some other day) 😉 So while I was browsing a random shop I came across the good ‘ol Academy Hobby Model Kits. I remember making a few of these models when I was younger. Feels great to be doing this again.
Tirpitz

Tirpitz - Click to see Hi-Res Image

I really enjoyed making this one. It even has a motor in it, and moves in the water. Maybe ill post pics once I muster up the courage to put all that hard work into the water.

Awesome photo above taken by my brother!

Cheers,

aero

Hello,

Welcome to my Blog. I hope you have a good time reading it.

Here I’m just gonna talk about things that interest me. It could range from (including but not limited to) my life, my hobbies, my work, or anything else I feel like writing about 😀

Cheers,

aero9