My suggestion is to learn this way . Say the words and go on.
But since this is hard to do. One automatically wants to go slow and get stuck.
לעולם לגרס איניש אע''ג דמשכח ודלא ידע נאי קאמר Talmud in Avoda Zara and Shabat 63a. [Brought in the Musar book the Paths of the Righteous.]
"One should always just say the words, and go on, even though he forgets and even though he does not know what he is saying."
Incidentally I asked my Dad "How did you get a Masters degree from The California Institute of Technology in one year? He always answered, "I worked hard." But still I said that is not enough. You have to be very smart for that. He answered, "I worked very hard." Later he invented stuff for the U.S.A. military. Once he got into Life Magazine for one invention. Later he worked on SDI/ Star Wars satellites.
I wrote a more complete essay on Physics in the other blog. Mainly it is about doing it first thing in the morning. The first twenty minutes after you wake up are crucial. Also. Coffee and tea in the same cup. [Israel Abuchatzeira had it that way.]
But mainly I think if you have only limited time you should just say the words in order until the end of the text and then do the same text [the whole book] four times. After four times you can go on. You might even think you did not get it. But you will be surprised after a few years that everything you learned starts to come together in your subconscious and you end up knowing what you thought you did not know,
1) How to learn Physics and Mathematics. My suggestion is to have one session right when you wake up in the morning. 20 minutes minimum, but it should be an hour. It should be in the way that the Talmud said--Say the words even though you forget and even though you do not know what you are saying. Don't review. But the next day you can review if you want. And in fact if you want to review the same material a lot of days in a row (e.g. forty days in a row), then that session will count as an in-depth session.
(The 20 min. idea I heard from a KGB agent that speaks perfect English. I asked how he did it. And he explained that he would learn it the first 20 min. when he wakes up and the last 20 min. before he goes to sleep.)
In any case, you need one in-depth session and one fast session. That fast one is also like the first, except you take a text of math or physics, and just say it from the beginning until the end, and you do that again until you have finished it four times.
The idea is that when you say the words a kind of outer light אור מקיף is formed around you. But you don't understand because the outer light has not come into you yet. So you have to say the whole textbook at least four times for the light to come in.
[I have sometimes look at Math in Hebrew, Russian and German and found that they sometimes explain things a lot more clear than you find in English. It helps me often to see how they explain things.]
2) This should be learnt with books of ethics and fear of God - before and after. Because the entire purpose of this is to bring one to see the wisdom of God as revealed in his creation. But for that to work, One's vector has to be towards God.
3) This is really the exact same thing as Talmud learning. Except for the Talmud if possible you need to get yourself a learning partner. But if that is impossible, then you do the same as I wrote here. You take one page of Talmud with the Tosphot and Maharsha and do the whole page--just saying the words. And the next day you go back and do it again for about forty days. Or until things start becoming clear. [That is the in depth session. The fast one is the same except the next day you go to the next page. I mean here what is called an half page.עמוד. A whole two sides is a lot to do with Tosphot. So I am asking only for one side of a page.] [Don't go to any synagogue to do this. Do it at home.]
4) In the morning I used to have a coffee or tea until I heard of the idea of Bava Sali (Israel Abuchatzaira) to have coffee and tea in the same cup.-. [I mean to say the first twenty minutes after you wake up are critical. You can take a few minutes to get the coffee and tea and learn Musar/ (books of ethics and fear of God). But this hard core Mathematics learning has to be the first thing. Before breakfast, before school, before davening (prayers). But obviously you say the "Shema Israel" right when you wake up.]
5) The most important thing to remember a little bit is also good. And not to be stubborn about anything in the world. Don't worry if you don't understand at first because eventually you will understand.
That is if you do this you will certainly know a lot more Physics than you do by giving up on it, or learning second hand trivial stuff.
6) And as for the desirability of this I defer to Maimonides in his Mishna Torah and More Nevuchim and my parents.
Though some people disagree with the Rambam in this, I feel they can't override him. In minor things or individual laws I do admit one should take the Rambam in the context of all the Rishonim [medieval authorities]. But an area that was a major thesis of his, I feel no one can override him. It is a heavily weighted variable for him.
I did not say anything about solving problems because I am addressing the need for general knowledge. As for individual problems, that is a whole other ball game.
Even for people that learn Torah all day I feel Physics and Mathematics are essential. See the introduction to the translation of Euclid by Baruch from Shkolov-the disciple of the Gra (Elijah from Vilnius).
7) I wanted to add that you don't have the right to claim you don't understand a physics or math textbook until you have read it--word by word, cover to cover, four times.
8) The way to understand this is to see that there are hidden levels of the human soul. And makifim. surrounding light. I could explain this more like Nietzsche and unconscious hidden levels that come close to the surface. But I would rather take an idea from the Ari. The idea is that when you say over the textbook--even if you don't understand it, you have one makif מקיף. a surrounding light that has gotten close to you by your saying the words. When you say the whole text again the outer light gets close to you. and when you do this in an environment where there are others also engaged in this the effect is stronger.