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| <meta name="author" content="Aliaksandr Melnichenka"> | |||
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| <meta property="og:title" content="Potential energy of interaction of a particle with a fixed point source U = V (\frac{l^2}{r^2} - \frac{2l}{r}), where r is the distance between the particle and the source, V and l are positive constants having the dimension of energy and distance, respectively. In what region does the rectilinear motion of a particle occur, if the total energy of the system is equal to E?"> | |||
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| <meta property="og:description" content="Potential energy of interaction of a particle with a fixed point source U = V (\frac{l^2}{r^2} - \frac{2l}{r}), where r is the distance between the particle and the source, V and l are positive constants having the dimension of energy and distance, respectively. In what region does the rectilinear motion of a particle occur, if the total energy of the system is equal to E?"> | |||
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| <title>Potential energy of interaction of a particle with a fixed point source U = V (\frac{l^2}{r^2} - \frac{2l}{r}), where r is the distance between the particle and the source, V and l are positive constants having the dimension of energy and distance, respectively. In what region does the rectilinear motion of a particle occur, if the total energy of the system is equal to E?</title> | |||
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| <h2>Solutions of Savchenko Problems in Physics</h2> | |||
| <p class="author"> | |||
| Aliaksandr Melnichenka <br/> | |||
| October 2023 | |||
| </p> | |||
| </header> | |||
| <h3 id="back-link"><a href="../../#2.3">$\leftarrow$Back</a></h3> | |||
| <h3> Statement </h3> | |||
| <p> | |||
| $2.3.40.$ Potential energy of interaction of a particle with a fixed point source $U = V (\frac{l^2}{r^2} - \frac{2l}{r})$, where $r$ is the distance between the particle and the source, $V$ and $l$ are positive constants having the dimension of energy and distance, respectively. In what region does the rectilinear motion of a particle occur, if the total energy of the system is equal to $E$? | |||
| </p> | |||
| <h3>Solution</h3> | |||
| <p> | |||
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| <p> | |||
| @@ -65,7 +65,7 @@ | |||
| Let us consider the case where the system (the second particle) starts moving at a distance $r$ from the first particle.</p><p> | |||
| Since this is the beginning of the movement, the kinetic energy of the first and second particles tends to zero. | |||
| − | $$E_{k1}\to | ||
| + | $$E_{k1}\to 0;\quad E_{k2}\to 0$$ | ||
| From where the total energy would be equal to the potential energy | |||
| $$E=E_p$$ | |||
| Substituting expression from the statement | |||
| $$\frac{E}{V}=\frac{l^2}{r^2}-\frac{2l}{r}$$ | |||
| Transforming it into a quadratic equation | |||
| $$Er^2+2Vlr-Vl^2=0$$ | |||
| @@ -75,7 +75,7 @@ | |||
| Let's solve it | |||
| $$r_{1,2}=l\frac VE\left(-1\pm\sqrt{1+E/V}\right)$$ | |||
| Since the distance is not less than zero, we choose a positive sign for $E>0$ | |||
| − | $$r\geq | ||
| + | $$r\geq l\frac VE\left(\sqrt{1+E/V}-1\right)$$ | ||
| For $E<0$ it will be in the range between $r_1$ and $r_2$ | |||
| $$l\frac VE\left(-1-\sqrt{1+E/V}\right)\leq r\leq l\frac VE\left(-1+\sqrt{1+E/V}\right)$$ | |||
| </p> | |||
| <h4>Answer</h4> | |||
| <p> | |||
| With $E>0$ area of motion $r\geqslant l\frac VE\left(-1+\sqrt{1+E/V}\right)$</p><p> | |||
| if $E<0$ area of motion, $r$ between $r_{1,2}=l\frac VE\left(-1\pm\sqrt{1+E/V}\right)$ | |||
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| <p style="text-align: right; font-style: italic; font-size: 14;"> | |||
| Almaskhan Arsen<br> | |||
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| <meta name="description" content="Potential energy of interaction of a particle with a fixed point source U = V (\frac{l^2}{r^2} - \frac{2l}{r}), where r is the distance between the particle and the source, V and l are positive constants having the dimension of energy and distance, respectively. In what region does the rectilinear motion of a particle occur, if the total energy of the system is equal to E?"> | <meta name="description" content="Potential energy of interaction of a particle with a fixed point source U = V (\frac{l^2}{r^2} - \frac{2l}{r}), where r is the distance between the particle and the source, V and l are positive constants having the dimension of energy and distance, respectively. In what region does the rectilinear motion of a particle occur, if the total energy of the system is equal to E?"> | ||
| <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"> | ||
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| <meta property="og:description" content="Potential energy of interaction of a particle with a fixed point source U = V (\frac{l^2}{r^2} - \frac{2l}{r}), where r is the distance between the particle and the source, V and l are positive constants having the dimension of energy and distance, respectively. In what region does the rectilinear motion of a particle occur, if the total energy of the system is equal to E?"> | <meta property="og:description" content="Potential energy of interaction of a particle with a fixed point source U = V (\frac{l^2}{r^2} - \frac{2l}{r}), where r is the distance between the particle and the source, V and l are positive constants having the dimension of energy and distance, respectively. In what region does the rectilinear motion of a particle occur, if the total energy of the system is equal to E?"> | ||
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| <header style="text-align:center;"> | <header style="text-align:center;"> | ||
| <h2>Solutions of Savchenko Problems in Physics</h2> | <h2>Solutions of Savchenko Problems in Physics</h2> | ||
| <p class="author"> | <p class="author"> | ||
| Aliaksandr Melnichenka <br/> | Aliaksandr Melnichenka <br/> | ||
| October 2023 | October 2023 | ||
| </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> | ||
| $2.3.40.$ Potential energy of interaction of a particle with a fixed point source $U = V (\frac{l^2}{r^2} - \frac{2l}{r})$, where $r$ is the distance between the particle and the source, $V$ and $l$ are positive constants having the dimension of energy and distance, respectively. In what region does the rectilinear motion of a particle occur, if the total energy of the system is equal to $E$? | $2.3.40.$ Potential energy of interaction of a particle with a fixed point source $U = V (\frac{l^2}{r^2} - \frac{2l}{r})$, where $r$ is the distance between the particle and the source, $V$ and $l$ are positive constants having the dimension of energy and distance, respectively. In what region does the rectilinear motion of a particle occur, if the total energy of the system is equal to $E$? | ||
| </p> | </p> | ||
| <h3>Solution</h3> | <h3>Solution</h3> | ||
| <p> | <p> | ||
| </p> | </p> | ||
| <center> | <center> | ||
| <figure> | <figure> | ||
| <img src="2.3.40.png" | <img src="2.3.40.png" | ||
| loading="lazy" width="230" /> | loading="lazy" width="230" /> | ||
| <figcaption> | <figcaption> | ||
| </figcaption> | </figcaption> | ||
| </figure> | </figure> | ||
| </center> | </center> | ||
| <p> | <p> | ||
| @@ -65,7 +65,7 @@ | |||
| Let us consider the case where the system (the second particle) starts moving at a distance $r$ from the first particle.</p><p> | Let us consider the case where the system (the second particle) starts moving at a distance $r$ from the first particle.</p><p> | ||
| Since this is the beginning of the movement, the kinetic energy of the first and second particles tends to zero. | Since this is the beginning of the movement, the kinetic energy of the first and second particles tends to zero. | ||
| $$E_{k1}\to |
$$E_{k1}\to 0;\quad E_{k2}\to 0$$ | ||
| From where the total energy would be equal to the potential energy | From where the total energy would be equal to the potential energy | ||
| $$E=E_p$$ | $$E=E_p$$ | ||
| Substituting expression from the statement | Substituting expression from the statement | ||
| $$\frac{E}{V}=\frac{l^2}{r^2}-\frac{2l}{r}$$ | $$\frac{E}{V}=\frac{l^2}{r^2}-\frac{2l}{r}$$ | ||
| Transforming it into a quadratic equation | Transforming it into a quadratic equation | ||
| $$Er^2+2Vlr-Vl^2=0$$ | $$Er^2+2Vlr-Vl^2=0$$ | ||
| @@ -75,7 +75,7 @@ | |||
| Let's solve it | Let's solve it | ||
| $$r_{1,2}=l\frac VE\left(-1\pm\sqrt{1+E/V}\right)$$ | $$r_{1,2}=l\frac VE\left(-1\pm\sqrt{1+E/V}\right)$$ | ||
| Since the distance is not less than zero, we choose a positive sign for $E>0$ | Since the distance is not less than zero, we choose a positive sign for $E>0$ | ||
| $$r\geq |
$$r\geq l\frac VE\left(\sqrt{1+E/V}-1\right)$$ | ||
| For $E<0$ it will be in the range between $r_1$ and $r_2$ | For $E<0$ it will be in the range between $r_1$ and $r_2$ | ||
| $$l\frac VE\left(-1-\sqrt{1+E/V}\right)\leq r\leq l\frac VE\left(-1+\sqrt{1+E/V}\right)$$ | $$l\frac VE\left(-1-\sqrt{1+E/V}\right)\leq r\leq l\frac VE\left(-1+\sqrt{1+E/V}\right)$$ | ||
| </p> | </p> | ||
| <h4>Answer</h4> | <h4>Answer</h4> | ||
| <p> | <p> | ||
| With $E>0$ area of motion $r\geqslant l\frac VE\left(-1+\sqrt{1+E/V}\right)$</p><p> | With $E>0$ area of motion $r\geqslant l\frac VE\left(-1+\sqrt{1+E/V}\right)$</p><p> | ||
| if $E<0$ area of motion, $r$ between $r_{1,2}=l\frac VE\left(-1\pm\sqrt{1+E/V}\right)$ | if $E<0$ area of motion, $r$ between $r_{1,2}=l\frac VE\left(-1\pm\sqrt{1+E/V}\right)$ | ||
| </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> | ||
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