The High School/College Thread (1 Viewer)

[Dome Vongvises]

How's mid-term for everybody.

My immuno test came back. A big 70. Technically, I can still get an A if I'm perfect for the rest of the semester. Riiight.....

I fucking hated that test. It's hard writing essays when you're thinking and writing under pressure.

 

[Scott_J]

Is this the week from hell for anyone else or just me? I have 2 papers I'm working on (one due next Tuesday), 2 mid-terms this week (Thursday and Friday), and I think I'm going to have to give a presentation Thursday in the class right after my mid-term.

And in about an hour I should get me grade for the first mid-term I took this semester.

 

[Dome Vongvises]

Any physics majors out there? How do you go about finding the local g (acceleration due to gravity) of your town? I'm not talking about an experimental value you derive yoursef, but a value that's been accepted or put into literature.

I'm getting points docked off my lab reports because I'm using 9.8 instead of my city's g. I hate my lab TA.

 

[NickSo]

3 midterms done, one to go!

PHILOSOPHY.. WHY DOE SIT HAVE TO BE SO... FRICKIN... PHILOSOPHICAL?!!!!

Fi anybody has any thoughts on MENO, SEXTUS EMPIRICUS or DESCARTES MEDITATIONS ON FIRST PHILOSOPHY im dying to hear them...

 

[Dome Vongvises]

Wish me luck on Physics this Thursday. Once again, slow poke Vongvises is going to find a way to not finish the test.

 

[CaseyLS]

Dome,
If I remember correctly it takes into account the elevation of your town and the air density. Probably wrong but maybe not.

 

[Mark Dubbelboer]

i got back my first midterm.

it says alot about the test when 38% of a graduate class gets below 40%.
my 70% is the happiest i've ever been when getting a test back. and on the plus side the final won't be hard anymore

 

[Scott_J]

The gravity equation I know takes into account the elevation of your town, as a ratio to the Earth's radius (6,370 km):

g(z)=[g0/{1+(z/a)}^2], with g0=9.8 m/s^2

Sinze z anywhere is negligible (essentially) compared to the Earth's radius, a, the whole equation just goes to g0/1^2 which is just g0, which is why 9.8 m/s^2 is used as the gravitational constant. ANY difference should be within +/- 1% of the accepted value (possibly even much less than 1% difference).

I actually had to do a problem on a homework set earlier this semester for my Dynamic Meteorology class, comparing g @ 10 km to g @ the surface (0 km). The difference between g(10km) and g(sfc) was .313% (9.7693 m/s^2@10km vs. 9.8 m/s^2@sfc). And the entire point of that problem was for us to realize the difference in g with height is negligible, and that meteorologists should not take into account the variation in gravitational values. Maybe that slight difference is significant in your physics labs - I don't know. But in my Physics lab I took last fall, we always used 9.8 m/s^2 for gravity, and it was acceptable.

 

[Dome Vongvises]

I don't know. But in my Physics lab I took last fall, we always used 9.8 m/s^2 for gravity, and it was acceptable.

Oh I wish that was in my case.

Just took my test this morning. Answered every problem fully except for one of them. Even in retrospect, I don't even know how to answer this:

A massless stick with length L has a mass m attached to it. The stick is attached at one end. An initial force F initial forces it to go in a circular motion in the vertical direction.

Using an expression that involves L, m, and F initial, to find the velocity of the mass when it makes a complete circle.

(Hint: remember the total work done by all forces and how the work/energy theorem relates to delta KE)


With the swiftness of a turtle, I had seven fucking minutes left on the test to work on this problem.

Since work is dependent on the force parallel/anti-parallel (eg. its horizontal component in most cases) to an object's displacement, I logically assummed that the total work in this case was zero, since the mass m returns to the original position (no net displacement).

I then tried to relate the changes in kinetic energy. The inital velocity is zero (or I like to think it is) so it will have a final velocity by the time it rolls back around.

I ran out of time by this point in thought process.

I hate bell curve tests.

 

[Dome Vongvises]

Oh yeah, here's the link to some of the practice exams. Keep in mind that I have no problem with how difficult the material is. I just hate the fifty minute time limit.

Click Here for test

Click here for class link with other tests

If you can finish the test in under fifty minutes, you're smarter than me.

Oh yeah, don't forget to show your work.

 

[Benny G]

I'll spew forth some good news. I'm a civil engineering student in my last year, and I got the highest midterms scores in each of my two design classes I'm taking this semester.

If anybody needs undergrad civil engineering help, feel free to shoot me an email...

 

[Benny G]

Dome, here's a wrong solution to your physics problem. It is, however, what I would write on my exam if I only had 7 minutes.

(Bear in mind that I took physics ages ago! Forget about the fact that I had dynamics last fall.)

The only way I can see to solve the problem is if you were given a time the force acted on the mass....or a distance...

So, I'll say that force effectively acted on the mass for a length of 2L, because it should take no force to move it horizontally - just vertically. The distance from the bottom to the top is 2L. I know I'm wrong here, but hey, I only have 7 minutes, right? I'm also assuming the non-massed end of the stick is attached to a pivot point or something (not sure if that really matters).

Thus,

2L * F(init) = 1/2*m*v^2

---> v = sqrt[4*L*F(init)/m]

 

[Dome Vongvises]

The only way I can see to solve the problem is if you were given a time the force acted on the mass....or a distance...

You're given no time.

This problem was on a test last year, and rumour had it that it created a lot of confusion because it wasn't clear whether or not the Force was acting on the mass for the entire time.

I get the test back on Wednesday, so I'll bring up the exact wording on the test.

 

[Benny G]

That's why I used a distance.

 

[Benny G]

Dome - any update on that exam problem?

 

[Dome Vongvises]

Yep, here's the wording:

A mass m is attached to one end of a massless stick of Length L that is pivoted about the other end. A force of constant magnitude Fo is applied to the mass in a direction always perpendicular to the stick (like a sideways pointing rocket tied to a stick). The mass, which starts at rest, thus executes circular motion in the vertical plane.

Derive an expression in terms of Fo, m, and L for its speed when it has completed a full circle.

The question was worth 13 points, and I got 10.

This is the solution:


v = sq root[(2piFoL)/m]

 

[Darren Davis]

Just wanted to chime in and exclaim my happiness that my 4000 word research paper (dubbed the "Extended Essay") that is a requirement for my HS diploma (International Baccalaureate programme) was turned in today at 3 PM. Ahh, such a huge weight off of me now. It's not the greatest thing I've ever written but I don't care...no more EE!

We're supposed to start research during the summer before our senior year and have a first draft ready for the first day of school. Then with our advisor we work out the kinks in subsequent drafts. Well, let's just say that I'm a procrastinator and started this thing only two weeks ago. I ended up taking off three days of school this week and staying up for about forty hours straight (I know, that's child's play to the grad student ) to finish it. Yay...time to party!!!! (and then do the rest of the homework I had to put off)

 

[Lowell_B]

Well, no better time than the present to chime in on a High School/College thread, I'm taking the SAT I tomorrow morning.

Then I gotta get prepared for the SAT II Subject tests in a month, then comes applications upon applications, yay!

Wish me luck, lol.

P.S. Remind me never to take college physics.

Lowell

 

[FredHD]

Ah school. I miss it (graduated with a BA in Radio, TV, and film in 98) I loved writing papers and hated tests. 800-1000 may seem tough in the beginning but it will become old hat. I once cranked out a 97 page screenplay over a weekend with 2 rewrites (I slept about a total of 10 hours over the three nights).

 

[Morgan Jolley]

Am I the only one who is only taking the SATs once and not taking SAT IIs? I got a 1430 the first time (last June) and am using that combined with good grades (and 3 AP classes: Calc, Phys, and French) to get into college (I applied Early Decision to U of Rochester).