# Most Frustrating, Embarrassing Brain Farts (1 Viewer)

### Users Who Are Viewing This Thread (Users: 0, Guests: 1)

#### Jilvin

I am a "physics guru", at least at my high school's level (which isn't really anything at all). I know several advanced integration techniques, linear algebra, and fairly advanced methods for solving differential equations. Even with all of this mathematics background, I still have not taken the AP Physics C exam due to my school's (in my personal opinion) lax curriculum not offering it as of now.
So, with my 8 dollar "University Physics" book, I scanned through to the "challenge problems" (which only take about a minute or two of thought to complete). One of the problems had me analyze certain properties of the equation (showing a velocity dependent force):

m(dv/dt)= Cv2

So, with all my arrogance and background, I tackled this problem. However, I soon became infuriated by the fact that I could not integrate the RHS with respect to time! I drastically manipulated differentials, but it was of no use! This simple problem had stumped me!

Then, about an hour after I had given up in despair, I realized that the left hand side of the equation existed and that I could divide by the v2 term to separate the variables. Wow. Just... wow. Does anybody else have these discouragingly terrible brain farts?

#### Acuben

oh ya I answered my age wrong ...twice -_-
I think I can think of e=mc^2 faster than my age xD

#### slider142

I think everyone has used a property of logarithms wrong at least once in a long, complicated problem and had to retrace their steps until they saw the boneheaded nonsense log(a + b) = log(a)log(b) in some dense block. Or maybe that's just me. :p
Also, 2 + 3 = 6, of course.

#### bp_psy

My theory is that 10% of all differentiations end up as integrations and 10% of integrations end up as differentiations..It's sort of like a mathematical uncertainty principle.

#### Borek

Mentor
Have you never canceled out 2s?

$$\frac 2 2 = 0$$

Gold Member

#### drizzle

Gold Member
...:shy:..........:grumpy:......----- Get it?!

#### lisab

Staff Emeritus
Science Advisor
Gold Member
Have you never canceled out 2s?

$$\frac 2 2 = 0$$
I probably have. I know for sure I did this once on a test:

(x + y)3 = x3 + y3

#### Pythagorean

##### excitation
Gold Member
Can't we talk about our infallible moments of lucid insight instead? Much shorter list.

#### imiyakawa

[PLAIN]http://profile.ak.fbcdn.net/profile-ak-snc4/object2/1868/74/n190172509102_8960.jpg [Broken]
[PLAIN]http://www.freewebs.com/fos08/Jokes/funny%20maths%201.JPG [Broken]
[PLAIN]http://haha.nu/files/uploads/farm1.static.flickr.com/170/371722884_a8d1da8f44_o.gif [Broken]

Last edited by a moderator:

#### Proton Soup

http://www.woosk.com/wp-content/uploads/2009/05/whale.jpg

#### DR13

Have you never canceled out 2s?

$$\frac 2 2 = 0$$
Way too many times...

#### GeorginaS

I probably have. I know for sure I did this once on a test:

(x + y)3 = x3 + y3

Eek!:rofl:

Then again, I can't even recall the last time I sat for a test that even remotely asked a question like that.

P

#### PracticeFish

##### Guest
I probably have. I know for sure I did this once on a test:

(x + y)3 = x3 + y3

Of course, one of x or y was 0, right? :tongue:

#### Upisoft

Of course, x=y=0, right? :tongue:
x=-y

PS: Hey! You did it actually in the thread!

#### Upisoft

x=-y

PS: Hey! You did it actually in the thread!
Damn, me too. There are 2 more solutions:
x = 0 and y = 0

#### Jilvin

I was asking you all for your personal worst brain farts, but posting complete nonsense is also fine I guess.

### The Physics Forums Way

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving