Memorizing All the Physics Formulas
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11-08-2016, 07:54 PM (This post was last modified: 11-08-2016 07:59 PM by cactus.)
RE: Memorizing All the Physics Formulas
Put your effort into the calculus right now, before getting too far into the physics equations. Trust me, it will be vital later on in college courses if you're going into a STEM field.

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11-08-2016, 08:11 PM
RE: Memorizing All the Physics Formulas
(11-08-2016 07:54 PM)cactus Wrote:  Put your effort into the calculus right now, before getting too far into the physics equations. Trust me, it will be vital later on in college courses if you're going into a STEM field.

Completely agree! Be one or two (preferrably two) math classes ahead of the prerequisites for your sciences.
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11-08-2016, 08:17 PM
RE: Memorizing All the Physics Formulas
Understanding why the formulae work and how they apply will likely be more useful than simply memorizing them. It will also help you remember them if that's what you really want to do.

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11-08-2016, 08:35 PM
RE: Memorizing All the Physics Formulas
I was hoping to put off Calculus as it is just to confusing for me. Yeah, maybe I should know why and how they work. Sadly I just do not know if my brain will be able to remember everything as it forgets a lot as it is.


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11-08-2016, 08:51 PM (This post was last modified: 11-08-2016 09:13 PM by cactus.)
RE: Memorizing All the Physics Formulas
(11-08-2016 08:35 PM)BlackWolf Wrote:  I was hoping to put off Calculus as it is just to confusing for me. Yeah, maybe I should know why and how they work. Sadly I just do not know if my brain will be able to remember everything as it forgets a lot as it is.

How well do you know algebra and trig? There was some trig stuff in Cal 1 that really pissed me off, because I had forgotten most of the trig identities from my high school algebra classes.
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Don't make rote memorization your goal. Try to understand as many of the basic concepts as you can from the ground up. As you learn new concepts, type equations into Wolfram Alpha and play with the variables to see how they affect the graphs.
In physics, you start by learning basic equations, and then the more complex stuff is just derived from there. Same with those godawful trig identities above. They make a lot more sense once you look up the proofs for each one.

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11-08-2016, 09:05 PM
RE: Memorizing All the Physics Formulas
(11-08-2016 08:35 PM)BlackWolf Wrote:  I was hoping to put off Calculus as it is just to confusing for me. Yeah, maybe I should know why and how they work. Sadly I just do not know if my brain will be able to remember everything as it forgets a lot as it is.

Focus on your GED, my friend. Don't worry about memorizing physics formulas until you get into college. No reason to put the cart before the horse.
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11-08-2016, 09:29 PM
RE: Memorizing All the Physics Formulas
I never took Trig in high school. Algebra I am a bit rusty on. I have been out of school for six years now.

As for the G.E.D that is a big loop. Honestly I do not see me getting it anytime soon due to not having money and a car. So I figure I should use what life I have to learn everything I can and just hope I do not die.


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17-08-2016, 08:31 PM
RE: Memorizing All the Physics Formulas
Depends entirely what you consider a formula in physics, to be honest. While there's definitely a handful of equations that are considered fundamental in certain disciplines (e.g. Maxwell's Equations in Classical Electrodynamics (CE), Shreodinger's Equation in non-relativistic quantum physics, Einstein field equations in general relativity, etc.) these are relatively few in number and honestly not the most helpful when you start including real-world complications.

Let's take Maxwell's Equations in CE. There's only four equations, right? Strictly speaking true, but to solve these equations you need to know the source terms (charge density and current) which is in general very difficult. Instead, a set of "macroscopic" Maxwell Equations are constructed which treat only the source terms you explicitly apply to a system (e.g. the current going through apparatus from your battery). The downside is now have six equations, which require the knowledge of two more "constitutive" equations. These equations are material specific, and as such impossible to know in general; however, a linear relationship (i.e. the electric field due to source terms you applied is proportional to total electric field) usually suffice but are still an approximation. So, by using that linear relationship, have you memorized a law of physics? And what about physics problems only amenable to numerical solutions?

I'm only going into this much detail since you say you want a Ph D. In terms of equations you see in class, you typically can memorize most core ones and key approximations (i.e. like the one I described above), but many formulae specific to certain problems will be forgotten but are, in principle, derivable from the core equations. E.g., I don't remember what the force on a block going on an inclined plane is specifically, but I can work it out. Most professors are aware of this, and I never found having to remember equations on an exam too difficult. Even the physics GRE--which is very notorious--often only expects you to remember proportionality relationships.

Anyway, need to do something, so that's all I say for now.
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17-08-2016, 09:17 PM
RE: Memorizing All the Physics Formulas
(11-08-2016 09:29 PM)BlackWolf Wrote:  I never took Trig in high school. Algebra I am a bit rusty on. I have been out of school for six years now.

As for the G.E.D that is a big loop. Honestly I do not see me getting it anytime soon due to not having money and a car. So I figure I should use what life I have to learn everything I can and just hope I do not die.

I went the college prep route in high school, but then kicked around for a bit, then joined the US Navy, kicked around for a year after that, and then went to university and earned a B Sc in Physics. There may be a way to get into the university, based on life experience, without a GED. You would have to check with the university. With enough motivation, a lot is possible.

If you don't have money or a car, a GED is one thing, but a university degree is going to be just as difficult. I don't know the particulars of your situation. Maybe look for a job with a company that would hire you if you had a degree in Physics, with an eye towards eventually getting that education (even though you don't have it now).
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17-08-2016, 09:27 PM
RE: Memorizing All the Physics Formulas
(17-08-2016 08:31 PM)ZoraPrime Wrote:  Depends entirely what you consider a formula in physics, to be honest. While there's definitely a handful of equations that are considered fundamental in certain disciplines (e.g. Maxwell's Equations in Classical Electrodynamics (CE), Shreodinger's Equation in non-relativistic quantum physics, Einstein field equations in general relativity, etc.) these are relatively few in number and honestly not the most helpful when you start including real-world complications.

Let's take Maxwell's Equations in CE. There's only four equations, right? Strictly speaking true, but to solve these equations you need to know the source terms (charge density and current) which is in general very difficult. Instead, a set of "macroscopic" Maxwell Equations are constructed which treat only the source terms you explicitly apply to a system (e.g. the current going through apparatus from your battery). The downside is now have six equations, which require the knowledge of two more "constitutive" equations. These equations are material specific, and as such impossible to know in general; however, a linear relationship (i.e. the electric field due to source terms you applied is proportional to total electric field) usually suffice but are still an approximation. So, by using that linear relationship, have you memorized a law of physics? And what about physics problems only amenable to numerical solutions?

I'm only going into this much detail since you say you want a Ph D. In terms of equations you see in class, you typically can memorize most core ones and key approximations (i.e. like the one I described above), but many formulae specific to certain problems will be forgotten but are, in principle, derivable from the core equations. E.g., I don't remember what the force on a block going on an inclined plane is specifically, but I can work it out. Most professors are aware of this, and I never found having to remember equations on an exam too difficult. Even the physics GRE--which is very notorious--often only expects you to remember proportionality relationships.

Anyway, need to do something, so that's all I say for now.

To Blackwolf--

I agree with what ZoraPrime is saying. There are actually very few actual equations that are "core equations" which have to be memorized. I have taught many first time students trying to learn Physics, and frankly I find the Algebra based Physics harder to teach due to its reliance on pre-derived formulas.

As a more introductory example for the original poster, the first few weeks of a college level Physics class is all about one and only one concept--constant acceleration motion. Very simple calculus can derive all those equations used in the introductory material, and basic vector math gets you through motion in multiple dimensions. Newton's laws of motion only really contain one equation to learn (F=ma = ∆p/∆t). And from that you already are half way through the first semester of College Physics covering motion, forces, and momentum.

Simple stuff, right? Of course not. If these concepts are so simple, then why all the derivations and equations? The rest of the equations are merely shortcuts in your toolbag so that each problem you work on doesn't take hours to solve. You learn a bunch of equations so that you can "do" Physics and solve problems. But to really get and understand the concepts at the level of a PHd, you should be learning Calculus based Physics because that will teach you how all the equations are derived. That means of course having a solid foundation of Calculus under your belt, and the sooner you tackle that, the better. If you can learn to derive everything in your Physics book from first principles, memorizing all the derived equations comes almost automatically without trying.
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