Updated greek laters @ latex compiling
en/2.3.30.md
+1 −1
| <!DOCTYPE html> | |||
| <html lang="en"> | |||
| <head> | |||
| <meta charset="utf-8"> | |||
| <meta name="viewport" content="width=device-width, initial-scale=1.0"> | |||
| <meta http-equiv="content-language" content="en"> | |||
| <meta name="keywords" content="Savchenko Problems in Physics, Savchenko solutions, physics problems, physics olympiad preparation, IPhO, Jaan Kalda"> | |||
| <meta name="description" content="Determine the force exerted on the vertical wall by the falling dumbbell when the dumbbell axis is at an angle lpha with the horizon. The dumbbell starts moving from a vertical position without initial velocity. Mass of each dumbbell ball m."> | |||
| <meta name="author" content="Aliaksandr Melnichenka"> | |||
| <meta name="date" content="2023-10" scheme="YYYY-MM"> | |||
| <meta property="og:title" content="Determine the force exerted on the vertical wall by the falling dumbbell when the dumbbell axis is at an angle lpha with the horizon. The dumbbell starts moving from a vertical position without initial velocity. Mass of each dumbbell ball m."> | |||
| <meta property="og:image" content="img/logo.png"> | |||
| <meta property="og:description" content="Determine the force exerted on the vertical wall by the falling dumbbell when the dumbbell axis is at an angle lpha with the horizon. The dumbbell starts moving from a vertical position without initial velocity. Mass of each dumbbell ball m."> | |||
| <meta name="yandex-verification" content="6cfda41f74038368"> | |||
| <title>Determine the force exerted on the vertical wall by the falling dumbbell when the dumbbell axis is at an angle lpha with the horizon. The dumbbell starts moving from a vertical position without initial velocity. Mass of each dumbbell ball m.</title> | |||
| <link rel="stylesheet" href="../../css/css-latex/style.css"> | |||
| <link rel="icon" href="../../img/logo.png" type="image/png"> | |||
| <script src="../../js/jquery-1.10.1.min.js"></script> | |||
| <script async src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.7/MathJax.js?config=TeX-MML-AM_CHTML"></script> | |||
| <script type="text/x-mathjax-config"> | |||
| MathJax.Hub.Config({ | |||
| extensions: ['tex2jax.js'], | |||
| jax: ['input/TeX', 'output/HTML-CSS'], | |||
| tex2jax: { | |||
| inlineMath: [['$', '$'], ['$', '$']], | |||
| processEscapes: true, | |||
| processClass: 'tex2jax', | |||
| ignoreClass: 'html' | |||
| }, | |||
| showProcessingMessages: false, | |||
| messageStyle: 'none' | |||
| }); | |||
| </script> | |||
| </head> | |||
| <body style=""> | |||
| <header style="text-align:center;"> | |||
| <a href="../../" style="text-decoration: none;"> | |||
| <div id="logo"> | |||
| <span><img src="../../img/book.png"></span><span>Savchenko Solutions</span> | |||
| </div> | |||
| </a> | |||
| <p class="author"> | |||
| Solutions of Savchenko Problems in Physics <br> | |||
| <i><b>knowledge must be free</b></i> | |||
| </p> | |||
| </header> | |||
| <h3 id="back-link"><a href="../../#2.3">$\leftarrow$Back</a></h3> | |||
| <h3> Statement </h3> | |||
| <p> | |||
| $2.3.30.$ Determine the force exerted on the vertical wall by the falling dumbbell when the dumbbell axis is at an angle $\alpha$ with the horizon. The dumbbell starts moving from a vertical position without initial velocity. Mass of each dumbbell ball $m$. | |||
| </p> | |||
| <center> | |||
| <figure> | |||
| <img src="statement.png" | |||
| loading="lazy" width="130" /> | |||
| <figcaption> | |||
| For problem $2.3.30$ | |||
| </figcaption> | |||
| </figure> | |||
| </center> | |||
| <p> | |||
| </p> | |||
| <h3>Solution</h3> | |||
| <p> | |||
| </p> | |||
| <center> | |||
| <figure> | |||
| <img src="draw.jpg" | |||
| loading="lazy" width="280" /> | |||
| <figcaption> | |||
| Forces acting on the system | |||
| </figcaption> | |||
| </figure> | |||
| </center> | |||
| <p> | |||
| Along the axis $OZ_\parallel$ "The Two-Ball System": | |||
| </p><p> | |||
| Centripetal acceleration associated with circular rotation: | |||
| $$a=\frac{v^2}{R}$$ | |||
| From the Newton's second law: | |||
| $$\frac{mv^2}{R}=2mg\sin\alpha-N_x\cos\alpha-N_y\sin\alpha$$ | |||
| Law of Conservation of Energy | |||
| $$mgR=mgh+\frac{mv^2}{2}$$ | |||
| $$h=R\sin\alpha$$ | |||
| $$\frac{mv^2}{R}=2mg(1-\sin\alpha)$$ | |||
| $$N_y\sin\alpha+N_x\cos\alpha=(4\sin\alpha-2)mg$$ | |||
| Along the axis $OZ_\perp$ "The Ball System": | |||
| @@ -95,7 +95,7 @@ | |||
| $$N_y\cos\alpha=N_x\sin\alpha+mg\cos\alpha$$ | |||
| $$N_y=mg+N_x\tan\alpha$$ | |||
| $N_y$ found from the axis $OZ_\perp$ we substitute into $N_y$ found from the axis $OZ_\parallel$ | |||
| − | $$mg\sin\alpha\cos\alpha+N_x\sin^2\alpha+N_x\cos^2\alpha=2mg(2\sin\alpha-2)\cos\alpha$$ | ||
| + | $$mg\sin\alpha\cos\alpha+N_x\sin^2 \alpha+N_x\cos^2 \alpha=2mg(2\sin\alpha-2)\cos\alpha$$ | ||
| $$\frac{N_x}{mg}=4\sin\alpha\cos\alpha-2\cos\alpha-\sin\alpha\cos\alpha$$ | |||
| $$\boxed{N_x=(3\sin\alpha-2)\cos\alpha \cdot mg}$$ | |||
| When $N_x \leq0$, the shoe will break away from the vertical wall and will no longer act on it: | |||
| $$N_x=0$$ | |||
| Condition of detachment: | |||
| $$(3\sin\alpha-2)\cos\alpha \leq0$$ | |||
| $$3\sin\alpha-2\leq0 \Leftrightarrow \boxed{\sin\alpha\leqslant2/3}$$ | |||
| </p> | |||
| <h4>Answer</h4> | |||
| <p> | |||
| $$F=mg\cos\alpha(3\sin\alpha-2)\mathrm{~with~}\sin\alpha\geqslant2/3;$$ | |||
| $$F=0\mathrm{~with~}\sin\alpha\leqslant2/3.$$ | |||
| </p> | |||
| <p style="text-align: right; font-style: italic; font-size: 14;"> | |||
| Almaskhan Arsen<br> | |||
| </p> | |||
| <footer class="row container"> | |||
| <br> | |||
| <p> | |||
| <small> © <strong>Savchenko Solutions</strong>, 2023-2024 <br></small> | |||
| </p> | |||
| <p> | |||
| <small>All rights belong to the authors. <br> Commercial use of materials - with the written permission of the authors. <br> alex@savchenkosolutions.com <br></small> | |||
| </p> | |||
| </footer> | |||
| </body> | |||
| </html> | |||
| ещё строк без изменений 28 | |||
| <!DOCTYPE html> | <!DOCTYPE html> | ||
| <html lang="en"> | <html lang="en"> | ||
| <head> | <head> | ||
| <meta charset="utf-8"> | <meta charset="utf-8"> | ||
| <meta name="viewport" content="width=device-width, initial-scale=1.0"> | <meta name="viewport" content="width=device-width, initial-scale=1.0"> | ||
| <meta http-equiv="content-language" content="en"> | <meta http-equiv="content-language" content="en"> | ||
| <meta name="keywords" content="Savchenko Problems in Physics, Savchenko solutions, physics problems, physics olympiad preparation, IPhO, Jaan Kalda"> | <meta name="keywords" content="Savchenko Problems in Physics, Savchenko solutions, physics problems, physics olympiad preparation, IPhO, Jaan Kalda"> | ||
| <meta name="description" content="Determine the force exerted on the vertical wall by the falling dumbbell when the dumbbell axis is at an angle lpha with the horizon. The dumbbell starts moving from a vertical position without initial velocity. Mass of each dumbbell ball m."> | <meta name="description" content="Determine the force exerted on the vertical wall by the falling dumbbell when the dumbbell axis is at an angle lpha with the horizon. The dumbbell starts moving from a vertical position without initial velocity. Mass of each dumbbell ball m."> | ||
| <meta name="author" content="Aliaksandr Melnichenka"> | <meta name="author" content="Aliaksandr Melnichenka"> | ||
| <meta name="date" content="2023-10" scheme="YYYY-MM"> | <meta name="date" content="2023-10" scheme="YYYY-MM"> | ||
| <meta property="og:title" content="Determine the force exerted on the vertical wall by the falling dumbbell when the dumbbell axis is at an angle lpha with the horizon. The dumbbell starts moving from a vertical position without initial velocity. Mass of each dumbbell ball m."> | <meta property="og:title" content="Determine the force exerted on the vertical wall by the falling dumbbell when the dumbbell axis is at an angle lpha with the horizon. The dumbbell starts moving from a vertical position without initial velocity. Mass of each dumbbell ball m."> | ||
| <meta property="og:image" content="img/logo.png"> | <meta property="og:image" content="img/logo.png"> | ||
| <meta property="og:description" content="Determine the force exerted on the vertical wall by the falling dumbbell when the dumbbell axis is at an angle lpha with the horizon. The dumbbell starts moving from a vertical position without initial velocity. Mass of each dumbbell ball m."> | <meta property="og:description" content="Determine the force exerted on the vertical wall by the falling dumbbell when the dumbbell axis is at an angle lpha with the horizon. The dumbbell starts moving from a vertical position without initial velocity. Mass of each dumbbell ball m."> | ||
| <meta name="yandex-verification" content="6cfda41f74038368"> | <meta name="yandex-verification" content="6cfda41f74038368"> | ||
| <title>Determine the force exerted on the vertical wall by the falling dumbbell when the dumbbell axis is at an angle lpha with the horizon. The dumbbell starts moving from a vertical position without initial velocity. Mass of each dumbbell ball m.</title> | <title>Determine the force exerted on the vertical wall by the falling dumbbell when the dumbbell axis is at an angle lpha with the horizon. The dumbbell starts moving from a vertical position without initial velocity. Mass of each dumbbell ball m.</title> | ||
| <link rel="stylesheet" href="../../css/css-latex/style.css"> | <link rel="stylesheet" href="../../css/css-latex/style.css"> | ||
| <link rel="icon" href="../../img/logo.png" type="image/png"> | <link rel="icon" href="../../img/logo.png" type="image/png"> | ||
| <script src="../../js/jquery-1.10.1.min.js"></script> | <script src="../../js/jquery-1.10.1.min.js"></script> | ||
| <script async src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.7/MathJax.js?config=TeX-MML-AM_CHTML"></script> | <script async src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.7/MathJax.js?config=TeX-MML-AM_CHTML"></script> | ||
| <script type="text/x-mathjax-config"> | <script type="text/x-mathjax-config"> | ||
| MathJax.Hub.Config({ | MathJax.Hub.Config({ | ||
| extensions: ['tex2jax.js'], | extensions: ['tex2jax.js'], | ||
| jax: ['input/TeX', 'output/HTML-CSS'], | jax: ['input/TeX', 'output/HTML-CSS'], | ||
| tex2jax: { | tex2jax: { | ||
| inlineMath: [['$', '$'], ['$', '$']], | inlineMath: [['$', '$'], ['$', '$']], | ||
| processEscapes: true, | processEscapes: true, | ||
| processClass: 'tex2jax', | processClass: 'tex2jax', | ||
| ignoreClass: 'html' | ignoreClass: 'html' | ||
| }, | }, | ||
| showProcessingMessages: false, | showProcessingMessages: false, | ||
| messageStyle: 'none' | messageStyle: 'none' | ||
| }); | }); | ||
| </script> | </script> | ||
| </head> | </head> | ||
| <body style=""> | <body style=""> | ||
| <header style="text-align:center;"> | <header style="text-align:center;"> | ||
| <a href="../../" style="text-decoration: none;"> | <a href="../../" style="text-decoration: none;"> | ||
| <div id="logo"> | <div id="logo"> | ||
| <span><img src="../../img/book.png"></span><span>Savchenko Solutions</span> | <span><img src="../../img/book.png"></span><span>Savchenko Solutions</span> | ||
| </div> | </div> | ||
| </a> | </a> | ||
| <p class="author"> | <p class="author"> | ||
| Solutions of Savchenko Problems in Physics <br> | Solutions of Savchenko Problems in Physics <br> | ||
| <i><b>knowledge must be free</b></i> | <i><b>knowledge must be free</b></i> | ||
| </p> | </p> | ||
| </header> | </header> | ||
| <h3 id="back-link"><a href="../../#2.3">$\leftarrow$Back</a></h3> | <h3 id="back-link"><a href="../../#2.3">$\leftarrow$Back</a></h3> | ||
| <h3> Statement </h3> | <h3> Statement </h3> | ||
| <p> | <p> | ||
| $2.3.30.$ Determine the force exerted on the vertical wall by the falling dumbbell when the dumbbell axis is at an angle $\alpha$ with the horizon. The dumbbell starts moving from a vertical position without initial velocity. Mass of each dumbbell ball $m$. | $2.3.30.$ Determine the force exerted on the vertical wall by the falling dumbbell when the dumbbell axis is at an angle $\alpha$ with the horizon. The dumbbell starts moving from a vertical position without initial velocity. Mass of each dumbbell ball $m$. | ||
| </p> | </p> | ||
| <center> | <center> | ||
| <figure> | <figure> | ||
| <img src="statement.png" | <img src="statement.png" | ||
| loading="lazy" width="130" /> | loading="lazy" width="130" /> | ||
| <figcaption> | <figcaption> | ||
| For problem $2.3.30$ | For problem $2.3.30$ | ||
| </figcaption> | </figcaption> | ||
| </figure> | </figure> | ||
| </center> | </center> | ||
| <p> | <p> | ||
| </p> | </p> | ||
| <h3>Solution</h3> | <h3>Solution</h3> | ||
| <p> | <p> | ||
| </p> | </p> | ||
| <center> | <center> | ||
| <figure> | <figure> | ||
| <img src="draw.jpg" | <img src="draw.jpg" | ||
| loading="lazy" width="280" /> | loading="lazy" width="280" /> | ||
| <figcaption> | <figcaption> | ||
| Forces acting on the system | Forces acting on the system | ||
| </figcaption> | </figcaption> | ||
| </figure> | </figure> | ||
| </center> | </center> | ||
| <p> | <p> | ||
| Along the axis $OZ_\parallel$ "The Two-Ball System": | Along the axis $OZ_\parallel$ "The Two-Ball System": | ||
| </p><p> | </p><p> | ||
| Centripetal acceleration associated with circular rotation: | Centripetal acceleration associated with circular rotation: | ||
| $$a=\frac{v^2}{R}$$ | $$a=\frac{v^2}{R}$$ | ||
| From the Newton's second law: | From the Newton's second law: | ||
| $$\frac{mv^2}{R}=2mg\sin\alpha-N_x\cos\alpha-N_y\sin\alpha$$ | $$\frac{mv^2}{R}=2mg\sin\alpha-N_x\cos\alpha-N_y\sin\alpha$$ | ||
| Law of Conservation of Energy | Law of Conservation of Energy | ||
| $$mgR=mgh+\frac{mv^2}{2}$$ | $$mgR=mgh+\frac{mv^2}{2}$$ | ||
| $$h=R\sin\alpha$$ | $$h=R\sin\alpha$$ | ||
| $$\frac{mv^2}{R}=2mg(1-\sin\alpha)$$ | $$\frac{mv^2}{R}=2mg(1-\sin\alpha)$$ | ||
| $$N_y\sin\alpha+N_x\cos\alpha=(4\sin\alpha-2)mg$$ | $$N_y\sin\alpha+N_x\cos\alpha=(4\sin\alpha-2)mg$$ | ||
| Along the axis $OZ_\perp$ "The Ball System": | Along the axis $OZ_\perp$ "The Ball System": | ||
| @@ -95,7 +95,7 @@ | |||
| $$N_y\cos\alpha=N_x\sin\alpha+mg\cos\alpha$$ | $$N_y\cos\alpha=N_x\sin\alpha+mg\cos\alpha$$ | ||
| $$N_y=mg+N_x\tan\alpha$$ | $$N_y=mg+N_x\tan\alpha$$ | ||
| $N_y$ found from the axis $OZ_\perp$ we substitute into $N_y$ found from the axis $OZ_\parallel$ | $N_y$ found from the axis $OZ_\perp$ we substitute into $N_y$ found from the axis $OZ_\parallel$ | ||
| $$mg\sin\alpha\cos\alpha+N_x\sin^2\alpha+N_x\cos^2\alpha=2mg(2\sin\alpha-2)\cos\alpha$$ | $$mg\sin\alpha\cos\alpha+N_x\sin^2 \alpha+N_x\cos^2 \alpha=2mg(2\sin\alpha-2)\cos\alpha$$ | ||
| $$\frac{N_x}{mg}=4\sin\alpha\cos\alpha-2\cos\alpha-\sin\alpha\cos\alpha$$ | $$\frac{N_x}{mg}=4\sin\alpha\cos\alpha-2\cos\alpha-\sin\alpha\cos\alpha$$ | ||
| $$\boxed{N_x=(3\sin\alpha-2)\cos\alpha \cdot mg}$$ | $$\boxed{N_x=(3\sin\alpha-2)\cos\alpha \cdot mg}$$ | ||
| When $N_x \leq0$, the shoe will break away from the vertical wall and will no longer act on it: | When $N_x \leq0$, the shoe will break away from the vertical wall and will no longer act on it: | ||
| $$N_x=0$$ | $$N_x=0$$ | ||
| Condition of detachment: | Condition of detachment: | ||
| $$(3\sin\alpha-2)\cos\alpha \leq0$$ | $$(3\sin\alpha-2)\cos\alpha \leq0$$ | ||
| $$3\sin\alpha-2\leq0 \Leftrightarrow \boxed{\sin\alpha\leqslant2/3}$$ | $$3\sin\alpha-2\leq0 \Leftrightarrow \boxed{\sin\alpha\leqslant2/3}$$ | ||
| </p> | </p> | ||
| <h4>Answer</h4> | <h4>Answer</h4> | ||
| <p> | <p> | ||
| $$F=mg\cos\alpha(3\sin\alpha-2)\mathrm{~with~}\sin\alpha\geqslant2/3;$$ | $$F=mg\cos\alpha(3\sin\alpha-2)\mathrm{~with~}\sin\alpha\geqslant2/3;$$ | ||
| $$F=0\mathrm{~with~}\sin\alpha\leqslant2/3.$$ | $$F=0\mathrm{~with~}\sin\alpha\leqslant2/3.$$ | ||
| </p> | </p> | ||
| <p style="text-align: right; font-style: italic; font-size: 14;"> | <p style="text-align: right; font-style: italic; font-size: 14;"> | ||
| Almaskhan Arsen<br> | Almaskhan Arsen<br> | ||
| </p> | </p> | ||
| <footer class="row container"> | <footer class="row container"> | ||
| <br> | <br> | ||
| <p> | <p> | ||
| <small> © <strong>Savchenko Solutions</strong>, 2023-2024 <br></small> | <small> © <strong>Savchenko Solutions</strong>, 2023-2024 <br></small> | ||
| </p> | </p> | ||
| <p> | <p> | ||
| <small>All rights belong to the authors. <br> Commercial use of materials - with the written permission of the authors. <br> alex@savchenkosolutions.com <br></small> | <small>All rights belong to the authors. <br> Commercial use of materials - with the written permission of the authors. <br> alex@savchenkosolutions.com <br></small> | ||
| </p> | </p> | ||
| </footer> | </footer> | ||
| </body> | </body> | ||
| </html> | </html> | ||
| ещё строк без изменений 28 | |||