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I don't like physics. A lot of people seem to think I do. I'd like to dispel those rumors: I don't like physics. Lucky for me, there are all sorts of majors here at MIT to choose from that have nothing to do with physics at all. I could be an electrical engineer, I could do brain and cognitive sciences, I could do chemistry or biology, or any number of different things. Which did I choose?
Mechanical Engineering.
I discovered something about mechanical engineering. Apart from physics, it has the most physics. Awesome, I picked a major that essentially is everything that I hate (physics) mixed with everything I love (building stuff).
Working my way through physics problems in high school, freshman year, and now during sophomore year I'm noticing a trend in physics problems: they get harder. Check this out
Junior Year of High School:
This is a nice summary of physics in high school for me:
We have an Honors physics class where nothing is being learned
We have an Asian (15% of the total asian population of my school)
We have an Hispanic (30% of the total hispanic population of my school)
We have a very difficult to build card house
We have a water bottle on said card house
We have more card house on said water bottle
We have the teacher taking a picture of the lack of learning in his class.
Needless to say things got different when I got to MIT.
Freshman Year:
What? You mean the horizontal component down the ramp is a sin instead of a cos!? Whoa dude, whoa.
And then, a little later. . .
Wait, blocks sliding on blocks? Wait, that doesn't . . . huh?
Sophomore Year:
This is when I realize that mechanical engineering = physics. I think it really struck me that physics was hard when I got this problem in my PSET that's due next week.
Yep, let's see, cart attached to wall with a spring, a pendulum attached to the cart, a force applied to the end of the pendulum, and a dashpot between the pendulum and the wall. Suck.
Flipping through my text book, I saw more and more physics, some of which actually would give me nightmares. I've scanned one of those nightmarish ones for you to see. Ready? Can you handle this?
AAAAAAAAAAAHHHHHHHHHHHHHHHHHHHHHHHH!!!!!!!!!!!!!!!! *faint*
Comments (Closed after 30 days to reduce spam)
My brain just turned to slush looking at the first picture of the cart attached to wall and etc etc.
Not to mention the second.
Posted by: wendi on November 14, 2008
Posted by: Ricky on November 14, 2008
But I want to be course 7 so it's all good. ^^
Posted by: 0 on November 14, 2008
Posted by: erik on November 14, 2008
This seems pretty scary, especially your last picture.
I think the best thing from this is not to feel discouraged from these example but to think that if I can get into MIT I will be able to learn how to solve all of these, hopefully
The harder the problem, the better you feel after being able to solve it, so after solving that last one ...
Posted by: Ivan on November 14, 2008
Maybe I'll just never understand
Posted by: Cristen on November 14, 2008
(Disclaimer: Yes, I am course 8)
Posted by: Eric '10 on November 14, 2008
Posted by: Bugg'12 on November 14, 2008
Posted by: deng on November 14, 2008
Posted by: Hafsa on November 14, 2008
*sees last picture*
ah...hehe, nevermind.
Posted by: 0 on November 14, 2008
Btw, when I saw that last problem, my first reaction was, "I can solve this" then, after the first three seconds *cryes a little*
Posted by: Patthysics on November 14, 2008
1st picture- I know this (yay for AP Physics)
2nd Picture- okay, I could work with this
3rg picture- uhhhhh...
4th picture- *head spin*
I actually have no idea how well I'm prepared for my major. I want to major in Chemical Engineering (Course 10, that is, if I get in). I get chemistry just fine, but I haven't exactly had a lot of exposure to fluid dynamics, thermodynamics, and a lot of other stuff I've never heard of that I'll run into.
Posted by: Matt A. on November 14, 2008
Posted by: anon on November 14, 2008
Posted by: Tiffany on November 14, 2008
Posted by: Anna on November 14, 2008
Posted by: Brian on November 14, 2008
Posted by: las1 on November 14, 2008
Posted by: wesh m on November 14, 2008
Posted by: Ehsan on November 14, 2008
string theory makes it all better : )
Posted by: alex on November 14, 2008
I would probably understand the questions, but what are you trying to find in the second diagram? There are like, 5 different variables.
Awesome post, by the way. They're the kind of things I need to wake my brain up.
Posted by: 0 on November 14, 2008
Posted by: Banerjee on November 14, 2008
By the way Snively, did you really had no idea that the horizontal component of a force(F) can be Fsin(angle)?
See you next year and have fun!
Posted by: Navdeep '13 on November 14, 2008
Don't put the cart before the horse, you have to get accepted first.
And no, I have no problem with the fact that the horizontal force is sine, it's just that normally it's cosine, a little counterintuitive.
Also, I'd be curious to see your solution for the cart-dashpot-pendulum one. Did you use Newtonian or Lagrangian mechanics?
Posted by: Snively on November 14, 2008
You're solving for the equations of motion. An equation that describes how the system moves.
Posted by: Snively on November 14, 2008
Posted by: 0 on November 14, 2008
Posted by: Colton on November 14, 2008
maybe u wont believe me snively but the first three probs are considered the basic and simple ones for 11th grade students here in my country (india) and we are given stuff that's sometimes even more stranger than the last picture you posted !!!!
you don't belive me ... ask a student there who has completed his high school in india ...
Posted by: navdeep on November 15, 2008
Posted by: navdeep on November 15, 2008
Nice post
Posted by: 0 on November 15, 2008
i would also like to say somthing about your previous reply to some other "navdeep" ....
you were saying that the horizontal component is generally cosine ....well to correct you ..it's not so ...cosine comp is the one which is connected with line subtending angle theta..and other becomes sine...
it doenst evn matters that which of the two from cosine and sin you use ..the only thing important is the angle which you use with them...you see we take cosine theta bcoz it's the angle bw mg nd mg cos theta ...yea dat angle is also equal to theta ...and if we would have written it like sin(90-theta) it wudnt have been wrong !!!!!!
Posted by: navdeep on November 15, 2008
In our AP Physics last year we had a problem which was something like the 3rd picture; we eventually did finish it although it took time. Just be neat on the working so you don't mess up and confuse two equations (like I ALWAYS do!).
@Snively
Do you like chem?
How much chem is there in Mechanical Engineering?
Posted by: Tree on November 15, 2008
Posted by: Anonymous on November 15, 2008
You're making MIT students sound like wusses. Man up, dude.
Posted by: lulu on November 15, 2008
Posted by: freshman on November 15, 2008
just sayin'.
Posted by: Keri on November 15, 2008
Posted by: another anonymous on November 15, 2008
Posted by: Chris on November 15, 2008
Posted by: Hiral on November 15, 2008
This is really forcing me to study mechanical engineering at college
Posted by: Junaid on November 15, 2008
Posted by: Navdeep II on November 15, 2008
Btw, the 4th diagram is plain evil :S
Oh, and @theNavdeepwho'ssuchagenius,
You sound like a lolcat.
Posted by: Ahana on November 15, 2008
Posted by: Ahana on November 15, 2008
well ahana i'm just like u -an indian student aspiring to be in MIT after clearing their high schools ...well in which state you are in ?
Posted by: navdeep on November 15, 2008
Yeah,you're right about the Qs. posted - I'm currently in 11th (in the CBSE syllabus) and the 1st 2 questions made some sense to me!
However,the last one looked terrible!!
@Snively
Even though I said the 1st 2 looked bearable - I'm the one who has the same thoughts in the resolution part (huh? the horizontal one's not always cos?!)
Anyway - you could check out our (NCERT)11th/12th grade books:D
Posted by: Vaibhav on November 15, 2008
Posted by: Vaibhav on November 15, 2008
yeah, i'm definitely not a huge fan of physics...brain/cogsci is more my thing =]
Posted by: hamsi on November 15, 2008
you say you can easily solve much harder mechanics problem than these but you can't comprehend the real intention behind Snively's post!
Posted by: saad(bahawlpur, pakistan) on November 15, 2008
Posted by: RZF on November 15, 2008
Posted by: surya on November 15, 2008
Posted by: Abdel-karim Moharram on November 15, 2008
I mean, each of these was hard the first time I got it. That's the point, right? Come to MIT, get PSET questions that you don't understand, solve them, learn.
Also, I'd rather make MIT students look like wusses than be super arrogant and brag about all the physics I know how to do.
@Everybody
The second one isn't that bad at all, that's why it's a freshman year, introductory physics, PSET 1 problem. The third one has all sorts of other stuff in the problem that I didn't post, including a bunch of stuff about Taylor series and stability.
The last one just looks like a mess. I've never tried to solve it, I don't know how hard it actually is.
What you'll notice about my entries is that I don't go into excruciating detail about everything. I'll give you a picture and a basic description and let you get on with your lives. I could go into a ton of detail about problems I've solved and the exact steps I took, but unless I made them colorful or through in some simplification nobody would read them.
Understand that there is often much more behind what I post that I'm just not showing you.
Posted by: Snively on November 15, 2008
Posted by: re: india on November 15, 2008
yea i understand now what you are saying ...
i'm sorry for starting this mess
Posted by: navdeep on November 15, 2008
Posted by: navdeep on November 15, 2008
Posted by: Dori on November 15, 2008
I also agree with u...most of the Indian students are genius in solving any sort of weird set of equations but they are limited in the practical application of this knowledge...
Posted by: 0 on November 15, 2008
(To all you physics geniuses: No blasphemy intended.)
Posted by: Niki on November 15, 2008
and how does "man up, dude" make MIT students sound like...dude? Especially when you say it to another fellow blogger. From this side, I think you're making MIT students sound like arrogant, juvenile, poorly spoken wusses.
I think there's a fine line between arrogance and confidence. Certainly, I have to say amen to, "...I'd rather make MIT students look like wusses than be super arrogant and brag about all the physics I know how to do."
Posted by: Patthysics on November 15, 2008
Interesting.
Posted by: Cam on November 15, 2008
Posted by: Amit on November 15, 2008
Posted by: Oasis '11 on November 15, 2008
can you please have a blog about nanotechnology at MIT? majors, courses, minors, whatever- I just really want to know.
Thank you
Posted by: nanofreak on November 15, 2008
Posted by: Liz on November 15, 2008
That a word like "hate" can stimulate debate is amazing? Write a blog entry about hating froyo and see how difficult it is to start getting people to argue. :p
Posted by: 0 on November 15, 2008
Posted by: lulu on November 15, 2008
Posted by: Cam on November 15, 2008
Burning question... Do professors usually assign psets over thanksgiving break that are due soon after? Or do you really get to give thanks for a 4-day break from the pset grind?
Posted by: Anonymous on November 15, 2008
Posted by: '12 on November 15, 2008
I dont think people understand the tone of your writing...especially the vertical cosine joke. I dont know what you intended to get from this blog-but I thought it was more of a fun read than anything. (I love the picture)
I admire those who attempted to solve the problems...the comments inpired me to try myself
Posted by: June on November 16, 2008
I think "Navdeep '13" is justified in writing his class(('13)), he is just trying to speak his goals. Research in Australia has shown that by BELIEVING in and SPEAKING our goals positively and optimistically, we can achieve them much faster than our peers(who are MOSTLY negative and lack confidence in themselves).
Also, we all understand your post, ALL the Navdeeps up there and me too have completed their high schools in India which must have greatly enriched their problem solving skills PLUS the basic understanding of PHYSICS in particular. They will all satisfy "MENS ET MANUS" (I think).
Posted by: Navdeep ('13?) on November 16, 2008
So now I feel a little more prepared for it MIT accepts me...some of the physics there is vaguely recognizable from my further maths classes here.
Which is comforting. XD
On the other hand, that last problem makes me want to cry. It looks horrible!
Posted by: Bethan on November 16, 2008
if u think speaking only can get u to ur goals then u r wrong.....nothing can be achieved without dedication and hardwork.....
u can try this...do 1 thing just keep saying optimistically to get in MIT......then we will see that the australian research holds good or not
Posted by: 0 on November 16, 2008
Posted by: Yan on November 16, 2008
Oh no! It seems I made an unintentional pun and can't even pick it out. Would you enlighten me? (By current I meant its uses in industrial applications and by potential I meant its viability for medicine delivery/hyperthermia/cool MEMS stuff).
Posted by: Liz on November 16, 2008
I was referring to electric current & magnetic fields / potential energies.
Posted by: Cam on November 16, 2008
Haha, that's very clever!
Posted by: Liz on November 16, 2008
mmm.. physics.. *drool*
Reading these blogs just makes me want MIT more. Hope it doesn't prove too elusive!
Posted by: Kaizad on November 16, 2008
(/me = /emote in some mmorpg's rofl)
Posted by: Dori on November 16, 2008
(In case you couldn't tell, I'm a bit of a physics nerd)
Nice house of cards, btw
Posted by: Robert on November 16, 2008
Posted by: 0 on November 16, 2008
@Snively: but those pictures look a lot better than they would with numbers. Conceptual problems make me happy.
@commenters from India: Indian high school students probably would do these kinds of problems in the 11th grade (though I'm still doubtful about the fourth one, I'm pretty sure that one is reserved for the precocious physicists in Olympiads and such). But guess what-- kids in the US taking AP Physics in 11th grade *also* do these kinds of problems! Snively's taking the courses at MIT because he said in an earlier post (excuse me if I'm wrong) that he didn't take AP Physics and thus didn't cover all of this. Besides, not everyone has to love physics.
My point is that if you can solve those problems, go you! Awesome! (Seriously, awesome.) But do you have to tell the world? :/ It's kind of beside the point of the post.
*Note: this is coming from an Indian student taking AP Physics in the 11th grade. So I know what I'm talking about when it comes to the material in the class, and I'm not hating on Indians-- India is pretty much amazing after all.
Still.
Posted by: Anonymous applicant on November 16, 2008
Posted by: Physics Fan on November 16, 2008
Posted by: Student on November 16, 2008
Are you taking B or C? I'm interested to know which one you're calling comparable. I took B last year, and we definitely didn't do problems like that third diagram.
For those unfamiliar with the AP program, there are 2 AP Physics courses. B corresponds a basic algebra based physics sequence that at other colleges might be taken by non-science majors to don't want to deal with the alternative. C is calculus based and corresponds to a class like 8.01 and 8.02 (there's a mechanics and an electricity and magnetism part) or a sequence that would be required for science or engineering majors at other schools.
Posted by: Matt A. on November 16, 2008
Posted by: Errina on November 16, 2008
Posted by: 0 on November 17, 2008
Please forgive me. I completely owe you an apology. I over-reacted to the lulu who responded deffensively in other posts by Snively. I abruptly took it seriously and not as a joke. Sorry^(forgivness number) =(
@Errina
lol
Posted by: Patthysics on November 17, 2008
c0, c1, and c2 are the coefficients for the damper. You know how F=kx for a spring (where x is displacement)? Well, F=cv for a damper (where c is velocity). It's the second term in an ODE, or think of it like a second order spring.
As for what you're solving for, you're trying to find the equations of motion. We use Lagrangians, but you can use just an ordinary force balance (it's just scarier). Your answer will be various derivatives of position (position, velocity, acceleration) mixed with coefficients and things. You should have one equation for every degree of freedom (ie, an equation for every cart).
Good luck!
Posted by: Snively on November 17, 2008
Posted by: 0 on November 17, 2008
Posted by: Vivi on November 17, 2008
The last problem...
Is there a point to it?
Physics is more than solving complex system s of forces that give you nightmares. Physics is the science of understanding the universe around us. It is the concepts that defines physics, not the complex nightmarish problems (although those are fun~).
Therefore, physics rocks!
Posted by: Ben Z on November 17, 2008
Exactly! XD
The second problem deeply disturbs me, but the last one looks like it would be fun to solve.
...
Wait, I left about 20 questions blank on the SAT Physics Subject Test!!! D:
(Is that related? No, but it's really fun to say.)
Posted by: José P. on November 17, 2008
(LAUGHS LOUDLY!)
Posted by: Navdeep ('13?) on November 17, 2008
@Anyone who knows:
What's the record for no. of comments for any blog entry on the MIT undergrad site??
Posted by: Vaibhav on November 17, 2008
If you think you outsmart the physics here at MIT then why the heck do you apply?MIT is a place for learning and improving not a place for those who have no room for improvement.
Posted by: XYZ on November 17, 2008
Posted by: maybe pre-frosh on November 17, 2008
IIT students in India seriously have no life! While they are really good at physics and math, that's all they know! MIT students are so interesting with a WIDE range of interests, while IIT students ONLY know numbers and exams!
Most of my best friends are IIT students and they have no interests in literature, sports, ECS, the world (honestly, they're obsessed with IIT!).
I used to be one of them untill I got sick of confining myself to only physics and math.
Sure, IIT students are probably the best physics and math problem solvers their age but honestly,only 1 or 2 out of a million IITians are actually interesting outside of their math and physics problems. I should know, I used to be one of *them*.
Posted by: 0 on November 17, 2008
Lagrangians rely on the principles of energy. The actual "Lagrangian" is equal to the kinetic energy of a system minus the potential energy of the system.
Basically, break your system down into several "admissible variations" (degrees of freedom, ways things can move, generally x, y, theta, etc). If there are no external forces, all you have to do then is take some derivatives of the Lagrangian with respect to your degrees of freedom and presto, answer. I can't really describe it all in one paragraph, but it's kind of magical. Look it up on wikipedia or opencourseware.
Posted by: Snively on November 17, 2008
good luck with that
Posted by: Aditi on November 17, 2008
Posted by: Kyle on November 18, 2008
firstly xyz ...huever you are ... i apologised to snively for starting this mess and the other thing is that i was'nt saying that i can outsmart all physics here at MIT ... i was just givin an opinion and that's one of the purposes blogs are made for ... they give people a chance to provide their opinions on a particular topic ...
but even then i say that if i offended you ..then I'M SORRY...
Posted by: navdeep on November 24, 2008
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