Ramos' penalty miss features in a third year university physics exam paper

beatrixasdfghjk. wrote:.
Well here, you don't have a calculator, then you just borrow one...
Our data sheet has mass of the Earth, and a whole bunch of formulae :L.

i guess it's very different how the U.S. operates. We use MKS units (kg, m, second), yet we measure and machine with inches, pounds.....
/facepalm

Calculators are indeed, borrowable. However, most of U.S. universities/colleges have like hundreds of people rolling in 1 physics class (lower div), as it is a requirement for many engineers, biologists, chemists, and many more. It's not practical buying like 10-20 calculators just in case. You can ask them to buy one, or have a cheat sheet with all the formula they can put in. That's fine too, but the best way is to deal with it alphabetically. It will also be easier for graders (imagine sig. fig throwing your answers slightly off, or you copied 1 number wrong onto your paper, which doesn't affect that many points anyways.). They tend to care more about the process, not the "answer". Most students wouldn't get all the answers right anyways.

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Don't you use those stuff because they're SI units and you have to, or the formulae go wonky?
As if your uni can't afford twenty calculators...

beatrixasdfghjk. wrote:Don't they give you data sheets?
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Well, Ramos didn't have a data sheet at hand and look at his shot!

beatrixasdfghjk. wrote:.
Don't you use those stuff because they're SI units and you have to, or the formulae go wonky?
As if your uni can't afford twenty calculators...

Yes, the formula goes weird when you have other units. Although arguably, most of them are just some random constants. But then, why would you ever want to make things more complicated? Haven't we already simplified things enough via (magic pulley with no friction, no viscious force- viscosity (my name too if you noticed ), ect....)

IE. when you learn coulomb's electric force between 2 charges (attract or repel), we have 2 formula. 1 is for cgs (centimeter, gram, second), and the other is MKS (meter, kilo, second). This is the difference....

where q1 and q2 are the charges, and k = 4pi elchilon (constant of permitivity, a very small number/constant) for MKS and k = c speed of light for CGS. They will save or spend your time if you have to manipulate this equation (multiply, divide, square, ect...)

The thing is, the world is using MKS, why bother using inches, pounds? It's not like all the american scientists are working with those units either. It's just the machinery and the arrogance. One can say that it's too complicated to change now, and that is partially true. Also, Benjamin Franklin got the sign wrong for + and - q. It turned out that he had 50% chance to assign the flow of electric current and it would take the whole western civilization down if we change it back.

But anyways, the MKS units are perfectly fine when it comes to classical mechanics like this. I, and many other people who majors in science/math are extremely annoyed when we have to convert things just because we are too stubborn to change.

Mind you, i wasn't born in U.S. either So i know how different americans are


As for the calculator, it's the department's choice. They have many classes as well as students. They aim is to test your ability to think logically, not the monkey plug and chuck. As long as you show your work, and make slight human errors, they will give you most of the point. In real life, computers would do most of the calculations. No one will sit there and chug in all the numbers while taking hundreds of data. That's why we also need to take programming classes. It's not hard, but the basic ones are essential. They don't care if you use calculational sites or programs like wolfram alpha, mathematicas to do differential equations (you might learn about this somewhat in spring, simple harmonic motion), or difficult integrals, ect....The numbers would also make answers different QQ. They will have to see if you really understand the materials or just mistakenly calculated wrong (plug in wrong, i do that all the time). It takes the grading process longer, and they CAN'T force you to do everything in alphabet until the end if it helps you organize the materials in a cleaner manner.

College shouldn't teach people to be monkeys....at least for math and physics majors.

What are you studying?
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You look like you could partner dos, majoring in either physics or maths .

Hey, I actually quite like conventional current and stuff being in the direction of positive charge, because it just feels quite retarded assigning a negative value as the positive direction...

beatrixasdfghjk. wrote:What are you studying?
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You look like you could partner dos, majoring in either physics or maths .

Hey, I actually quite like conventional current and stuff being in the direction of positive charge, because it just feels quite retarded assigning a negative value as the positive direction...

i don't know who that is, but i am currently stepping in 3rd year physics at a uni :S Was very shocked to see that question on the exam...i used to do similar ones during my senior year in high school, and i guess you are doing the same thing right now!

As for the flow convention, he had 50% chance. This is the convention



However, once you study further, you will understand that electric currents happen because electrons migrate. In conductors like coppers, or metals, electrons can flow freely, which can put one side extremely positive (lack of electrons), and the other negative (extra electrons). The fact that the electrons are moving toward the positive charge (opposite attracts) tells you that field lines should run from negative to positive. Same with circuits. However.....well, the picture above basically tell you what the convention made by Benjamin was. It was not wrong, it's arbitrary, but Electrical Engineers hate him

Dos is a mod, you should come visit the Australian section . We already have one American there...
Yeah, we got told field lines go in the direction a positive test charge would move when placed at that point, even though it's actually the electrons moving .