17:08 If you had written the first term in the formula of integration by parts in the form (fg) without the integral and the prime, it would be better, since you'll only have to write partial(L)/partial(q_dot) delta(q) evaluated at the boundary conditions which would make it clearer + it's a better way in introducing the formula of integration by parts.
24:35 How would this work, say in the case of a projectile with a quadratic drag, where the solution cannot be split into a horizontal and vertical equations. Is this derivation even valid in that case? Doesn't it assume that motion is separated between the coordinates? Is that related to how we define the generalized coordinates? or does the fact that it's analytically unsolvable for a general solution makes it impossible to describe with Euler-Lagrange equation?
@mohad12211 Good question. This is something that I will clarify in the upcoming videos in sha Allah, but here is the short version. Your question has several points mixed up, so let's break down few things. First, the Lagrange equation as described and derived in this video, and in Landau's book at this stage is NOT the generalized equation. In other words, it only deals with conserved systems. For the Lagrange equation to accommodate a non-conserved force such as the air drag, there will be another term added for the generalized forces. This is something I will hint at in the future without going into the details. I am mostly interested in conserved systems. The second, and more important part, is that the Lagrange equation doesn't give you the solution of the mechanical system, it only describes it. That is to say, the Lagrangian model, same like the Newtonian model, only gives you the equation of motion, which is usually a second order differential equation that you still have to solve. That differential equation might be non-linear equation that cannot be solved analytically. This doesn't have to be a non-conserved system. For example, the simple pendulum is a non-linear system even without any resistive force.
في هذا الفيديو تحديدا كان لازم أستخدم قلم خطه أرفع لأن المعادلات كانت طويلة و كثيفة. لو أستخدمت القلم الكبير كانت الخطوات هتتفرق في عدد أكبر من الصفحات مما يصعب ربط الخطوات ببعضها. باختصار, كنت محتاج أكتب أكبر قدر من المعادلات في أصغر مساحة ممكنة
مبارك لحضرتك على ال ٢٠٠ ألف
إن شاء الله القناة توصل للمليون 🤍
الجمال كله 🌷
بارك الله فيك أستاذنا، الحقيقة أبدعت في الكلام عن مفكوك تايلور.
جزاكم الله خيرا أخي الكريم
نحبك يا دكتور استمر ❤❤❤
والله بحبك في الله
يامعلم (استاذ) احبك في الله
❤
جزاك الله خيراً يا بشمهندس ❤
عوده حميده يا معلمي الفاضل
أدام الله عليك بالصحة والعافية ❤
17:08
If you had written the first term in the formula of integration by parts in the form (fg) without the integral and the prime, it would be better, since you'll only have to write partial(L)/partial(q_dot) delta(q) evaluated at the boundary conditions which would make it clearer + it's a better way in introducing the formula of integration by parts.
جزاك الله خيرا، متتاخرش علينا يا هدنسه
شكرا 🌹
الورق الاصفر ده نوعه اي😅
اسمه ورق دشت بتشتريه بالكيلو تقريبا
السلام عليكم يا دكتور
القلم اللي حضرتك بتستخدمه في فيديوهات light board اسمه اي
على فكرة نقدر نخلينا rigorous اكتر بإننا نحسب الfunctional derivative بدل الvariation.
δS/δq
استاذ هل ستتطرق إلى oscillations??
machhalah
Bro ,The right is Mashallah
Not machhalah
24:35
How would this work, say in the case of a projectile with a quadratic drag, where the solution cannot be split into a horizontal and vertical equations.
Is this derivation even valid in that case? Doesn't it assume that motion is separated between the coordinates?
Is that related to how we define the generalized coordinates? or does the fact that it's analytically unsolvable for a general solution makes it impossible to describe with Euler-Lagrange equation?
@mohad12211
Good question. This is something that I will clarify in the upcoming videos in sha Allah, but here is the short version.
Your question has several points mixed up, so let's break down few things.
First, the Lagrange equation as described and derived in this video, and in Landau's book at this stage is NOT the generalized equation. In other words, it only deals with conserved systems. For the Lagrange equation to accommodate a non-conserved force such as the air drag, there will be another term added for the generalized forces. This is something I will hint at in the future without going into the details. I am mostly interested in conserved systems.
The second, and more important part, is that the Lagrange equation doesn't give you the solution of the mechanical system, it only describes it. That is to say, the Lagrangian model, same like the Newtonian model, only gives you the equation of motion, which is usually a second order differential equation that you still have to solve. That differential equation might be non-linear equation that cannot be solved analytically. This doesn't have to be a non-conserved system. For example, the simple pendulum is a non-linear system even without any resistive force.
لو سمحت ممكن حضرتك ترجع تستخدم القلم القديم، لأن خطه اوضح و أسهل في القراءة.
في هذا الفيديو تحديدا كان لازم أستخدم قلم خطه أرفع لأن المعادلات كانت طويلة و كثيفة. لو أستخدمت القلم الكبير كانت الخطوات هتتفرق في عدد أكبر من الصفحات مما يصعب ربط الخطوات ببعضها.
باختصار, كنت محتاج أكتب أكبر قدر من المعادلات في أصغر مساحة ممكنة
@@anaHr
جزاك الله خيرا
الخط واضح وكل حاجه تمام
في حاله انك عايز مساحه ممكن تخلي الورقه بالعرض مش بطول
او ممكن تجيب ورقتين جنب بعض وتكتب كنها ورقه واحد
أستاذي الفيديوهات علي البلاي ليست دي مش مرتبه ، ارجوك خليها بالترتيب
جزاكم الله خيرا علي التنبيه
@@anaHr جزاكم مثله يا أستاذي ومعلمي