Questions tagged [homework-and-exercises]
Applies to questions of primarily educational value - not only questions that arise from actual homework assignments, but any question where it is preferable to guide the asker to the answer rather than giving it away outright. Please READ THE GUIDANCE IN META before asking homework-like questions.
23,680 questions
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How do I find work done by friction over a curve represented by a polynomial?
I am facing a problem in Physics. Problem: What will be the work done by the frictional force over a polynomial curve if a body is sliding on this polynomial($a+bx+cx^2+dx^3+\ldots$) curve from rest ...
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1answer
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EM Wave Reflection and Transmission Between with Anti-Reflective Coating
I am trying to solve a problem in which light is normally incident on a material of refractive index n which is coated with an anti-reflective coating of refractive index $n^{\frac 1 2}$ and thickness ...
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Finding Locally flat coordinates on a unit sphere
I know this is more of a math question, but no one in the Mathematics community was able to give me an answer, and since physicists are familiar with General Relativity, I thought I might get an ...
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Schrodinger equation has NO solution for infinite-finite potential well?
Consider the following potential $$V(x)= \begin{cases} +\infty, &x<x_0 \\ 0, & x\in[x_0,L] \\ V_0, &x>L \end{cases}$$ and the associated time-independent Schrodinger equation $$-\...
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Examples of central forces on the path of orbit?
In solving a problem from Goldstein (3.13), I solved for multiple properties of a circular orbit with the attractive central force where the path of orbit crosses the point of the force (at origin). ...
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Finding velocity of the bob of a pendulum without 'Work energy conservation' (Non SHM) [closed]
The situation is as follows:- A pendulum is fixed to a horizontal roof. The free end is is taken aside so that the thread forms a right angle with the vertical and then it is released. Find the ...
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The modular transformation of coordinate on torus
In 2D conformal field theory, the modular transformation of torus is defined by the fractional linear transformation \begin{equation} \tau'=\frac{a\tau+b}{c\tau+d},~~ad-bc=1,~a,b,c,d\in Z. \end{...
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How to compute symmetry factors of Feynman diagrams: two-point correlation function of $\varphi^4$-theory up to the fourth order? [closed]
I'm a bit struggle with the computation of the symmetry factors of the 2-point correlation function in Feynman diagrams for the $\varphi^4$ theory. I'm using the formula found in "Gauge theory of ...
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Net flux through insulating cylinder
In a non-uniform electric field, say with field lines curving away from each other along x, will the net flux on a cylinder be negative or zero?
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How can we derive the maximum scattering angle from the experiment of Geiger and Marsden?
Schematic diagram of apparatus used by Geiger and Marsden to observe scattering of $\alpha$ particles past 90°. "A small fraction of the $\alpha$ particles falling upon a metal foil have their ...
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Calculating the equilibrium temperature of a bob and water system when energy can be lost to the surroundings via heat [closed]
Let's say we have an aluminium bob at X degrees Celsius, and we have a water container at Y degrees Celsius. I am assuming here that the initial temperature of the container and the surroundings is ...
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Derivative with respect to a metric [closed]
Im trying to understand why $$\frac{\delta (A^0 J_0)}{\delta g^{\mu\nu}}=A_\mu J_\nu g^{\mu 0}\delta ^{\nu}_{0},$$ because I tried to write $$A^0 J_0=A^0 J_0 g_{00} g^{00}$$ since $$g_{00} g^{00}=1,$$ ...
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2D Elastic collisions and relative velocities
As mentioned in every text book I own, the relative velocities of approach and separation are equal and opposite for (only) 1D collisions. For 2D collisions, only the component of velocities along the ...
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Polarization of Light from a Surface at an Angle [closed]
I have this problem from Bennett Principles of Physical Optics $3.65$ "A photographer wishes to use a linear polarizer in front of the camera lens to reduce glare from a surface with normal ...
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Need help interpreting displacement-time graphs
In this image is a displacement-time graph of the movement of an object. In the video (Khan Academy), the explanation is that between $0\,\text{s}$ and $5\,\text{s}$, the displacement of the object is ...
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