The Hardest Exam I Ever Took at MIT in Physics

I did fail a math exam.

My very first math exam-- I think I got a 10% or something like that.

I mentioned before we filmed I got a minus 5 on a math exam once.

Hey, I'm Dianna.

You're watching Physics Girl.

And I'm here today with Toby from the channel Tibees, one of the other physics channels on the interwebs.

Toby does this really cool thing on her channel where she unboxes physics exams.

The concept-- you might have seen it with Tik and new iPhones and stuff, very exciting, capture people's reactions.

I do that but with exams.

We're going to look today at some exams from MIT, which is where I went to college, specifically 8.012, which was my first physics class at MIT.

It was mechanics, but we lovingly called it mechanics for masochists, because it was very, very hard.

We'll have to have a look and see what the problems are like and why it would get that reputation for itself.

We're going to talk a little bit about exam tips and tricks at some point for you physics students out there.

All right, let's get to it.

You're going to have to teach me how to do this.

I don't unbox.

Yeah, so let's do an unboxing.

So in your sleep-deprived state, you open it, and you look at this, so this is the first problem.

And it looks like we're starting off with some multiple-choice and short-answer questions.

The first one here-- two planets are orbiting a star at two different radii.

And then they're asking which has the greater orbital velocity and which has the greater angular momentum.

So you'd need to know how the orbital speed depends on the distance away from the star.

You're not just asked for the formula or to plug numbers in.

They're actually asking you how are these things related, so maybe that's why it's a harder course.

Yeah, which is something I really liked about this course, is that it was conceptual.

You didn't just plug in equations.

You had to know the physics concepts.

And I think that's partially why conceptual physics is my favorite way of thinking about physics.

The math is fun.

Don't get me wrong.

That's why I'm wearing it all over my jacket.

Cool.

Next one.

I feel like you should have done the page turn.

Oh, no, no.

You need to learn-- you need to learn the technique.

On to problem number 2, the Atwood machine.

These usually take a while to work through.

And they're not that conceptually hard.

It's just usually a bit of algebra, determining, in part B, the acceleration of the lighter blocks, so knowing how forces are related to acceleration, I guess-- F equals ma.

If you know that much, you'll probably do OK on the question.

It's a bit intense looking.

It is intense looking.

A lot of times, they'll have no friction in problems like these.

But this one-- they've got a coefficient of friction.

Let's keep going.

Oh, a rocket.

Oh, this one looks fun!

Rocket in an interstellar cloud.

I'm going to guess that this problem is something like, you've got this density of particles over here, and you've got a velocity.

So it's how much the rocket slows down or how much it has to continue boosting itself in order to overcome the momentum lost from hitting wedge particles.

So the fact that you're there breaking down the rocket into two different masses is, I guess, rocket science and the basics of rocket science here.

This is when math comes into physics, is you're losing fuel, but we're going to reflect that in terms of a change in mass of the rocket, which is cool.

Yeah, and I think the rocket equation and stuff like this is actually really cool physics.

My one tip for going into any physics exam is just F equals ma.

Here, they give it to you in the question, which is great.

But when in doubt, try to smush something into F equals ma, and you'll probably come out with something.

The problem here is that m is changing.

Moving on.

Moving on, we've got something called sticky disks.

And this looks like a momentum conservation thing.

I guess we could actually read the question, but that's just my initial thoughts.

And so if I had turned over the page and seen that, I would have been ready in my brain with momentum is mv, and momentum is conserved in a system like this.

You know what we haven't done so far, which I would often do in exam, is to look just through all the questions.

We could just flick through the rest of it.

Yeah, let's do it.

Oh my goodness.

This is a very long question.

Obviously something about rotation.

This has got to be rolling in somehow.

Next would be bead on a spinning rod.

There's a lot of rotation, but there's also motion.

Yeah, it's a lot of cases of things rolling, moving, rotating, and sliding.

Central potential-- OK, so we've got a little bit of potential energy question, it looks like.

Particles, so-- Oh, and then they give you some equations.

That's so nice.

Probably not good to see at the end of the exam.

Good to see these before you start.

Oh, these are nice.

You can see how these would be useful.

These are moment of inertia of different shapes.

These are things that I would not-- deriving the moment of inertia of different shapes would take forever.

We've got F equals ma.

There's potential energy in integral form.

We've got work.

Yeah, you can see that calculus is involved in this course, because they're all written in integral form and whatever.

OK, cool.

I think we're done with 802 final.

Yay, we passed.

High five.

Yay.

Show us what you should.

OK.

So this is the very first exam that I took in 8.012, physics for masochists.

[CLANGING SOUNDS] 2007, that fateful day.

OK, here's this problem, number 5.

Out of 25 points, I got one, one point.

So I got an 8 out of 10 on the first problem, so that's good.

Oh, I got the direction of friction wrong.

How could I say there was no friction action on the tire?

I wonder what I was thinking.

Oh course there's friction.

Look, I think it's a common thing for people to look back on their exams with the phrase, what was I thinking?

Circle the point where the magnitude of acceleration is the greatest.

Well, I did pretty good there, because of all the multiple-choice ones I got it right.

What else have we got?

Oh, I got these right too, Yay.

And then it goes downhill from here.

Yeah, so you can see you did a lot of algebra.

You had to set up these equations and then manipulate them to cancel terms.

And I think that's where people can go wrong, because it's like you've barely got enough space to answer the question, first of all.

Yeah, yeah.

Hey, look, F equals ma.

What else have we got?

"Watch out the algebra," is what somebody wrote when they were grading this.

This problem-- this is one that I actually remembered.

The rest of these-- poof, gone from my memory.

But this one I remember.

What is the period of oscillation of the disk?

I will never know, because I got a zero.

Doesn't stress make you remember situations more, which is why you remember this question?

Because you were traumatized.

Maybe so.

I actually did, in the end, pass this class.

This was 8.012.

Then, 8.022, I got an A.

So I learned how to do MIT.

So can we pause for just one second and talk about exam tips and tricks, like best practices?

Because it's been a while since I've taken physics exams, but I do feel like I learned a lot of techniques.

I didn't really look at practice problems much before I got to college.

I just thought I knew the material, and I was ready to go, but as soon as I got to MIT and got to some harder material, one thing we would do that really helped was looking at old practice exams from previous years of the course.

I almost feel like that is the most useful way to study for an exam.

Past exams are such a good way to study because they tell you the format of the problem.

Even if the problems aren't the same, they let you know how much time you've got, how much time you should be allocating.

You're not going to get better just by only reading solutions.

You have to read them and then try yourself.

And actually, I think a good thing to do is try until you get stuck.

If you're really stuck, and you've explored the avenues, look at the solutions.

But you don't need to look at the whole thing.

You can just look at the first line that gets you off the hurdle you're on, and then keep going until you get to the next hurdle.

And I think that's a good way to train yourself how to finish the problem.

Another tip for exam preparation-- it's related to looking at solutions in the same way, but it would be working in a group for at least a little bit of time while you're studying.

I experienced nearly failing a number of my courses freshman year.

I came into MIT not prepared for the rigor of MIT.

I didn't just almost fail this exam.

I did fail a math exam, my very first math exam-- I think I got a 10% or something like that.

I mentioned before we filmed I got a minus 5 on a math exam, once.

That's impressive.

I did end up passing the course with an OK grade as well.

I ended up passing the class with a B.

So I retook that exam, and I got a 90 something on the retake of the math exam.

And it was just purely from learning how to study for the exams.

And the biggest things were doing the practice problems.

I mean, honestly, that was it.

Do the practice problems.

Because that helps you with everything else.

It helps you with time management.

So that's 8.012.

Thanks for looking at the exam with me.

Glad to have done another MIT one.

It brings back good memories, good and bad, mostly.

Don't be intimidated, though, if you're watching and you didn't understand the questions.

You really need to be in the class.

Definitely go over and check out Toby's channel.

We did that entrance exam to get into MIT in 1867.

It was really cute.

We just looked at the geometry section, but I'll put a link in the description.

So check out and subscribe to Toby's channel.

Do you know my signoff?

Happy physics-ing?

Yes.

Thanks so much for watching, and happy physics-ing.

Happy physics-ing.

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