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.
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I am trying to derive an expression for the magnetic field of charged particles travelling at significant fractions of speed of light [closed]
I tried using lorentz transformation , which gives me correct answer for speed of light c but when i try to input any other values nearby c it becomes a constant
B = 10-7 . q/r² ( (v - u)/ 1- uv/c²)
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Average Force using Heisenberg Equation on a bounded particle [closed]
My problem states: Prove that the average force that acts on a bounded particle is zero.
Before I write what I have so far, I have a question, ¿How do we represent a bounded particle? I believe that a ...
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Orthogonal complement of null vector [closed]
I am trying to solve excercise 8.5 d) from Straumanns book on general relativity (here V is an n-dimensional Minkowski vector space):
Prove that the orthogonal complement of a null vector is an $(n-1)$...
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Issue with simplifying the equation related to non-uniform acceleration [closed]
I am exploring how the cross sectional area of a drogue chute affects its velocity after travelling a set distance.
I got this equation:
$$m_1 a = m_2 g - \frac12 c_d \rho A v^2,$$
This covers the ...
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How to calculate the relative speed when three bodies are involved? [closed]
Two trains A and B start from a station and move in parallel tracks with velocities 40 kmph and 60 kmph respectively. A man sitting in train A. watches a lady who walks inside the train B at a speed ...
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For an objective falling, reaching terminal velocity and then hitting the ground, how can I find the force it exerts on the ground? [closed]
For example object with v=tanh(0.1213)t/0.01236. m=69kg.
I thought I had to use F=mv/t but that just gives the net force of the object while falling.
I don't know how to find the force impacting on ...
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Thermodynamics exercise on transformations
An exercise in my book states the following:
n = 0.42 moles of an ideal biatomic gas are stored in an adiabatic cylinder with volume $V = 10^{-2} \text{ m}^3$, with an initial pressure equal to one ...
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Extrinsic Curvature Calculation on the Sphere
Given the following 2+1 dimensional metric:
$$ds^{2}=2k\left(dr^{2}+\left(1-\frac{2\sin\left(\chi\right)\sin\left(\chi-\psi\right)}{\Delta}\right)d\theta^{2}\right)-\frac{2\cos\left(\chi\right)\cos\...
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Force acting on an infinite wire with current inside a magnetic medium
I've recently stumbled on an electromagnetics problem that I don't quite understand.
There is an infinite wire carrying current I that is placed inside a medium with magnetic permittivity μ1. At a ...
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Extra force in other frame paradox
Suppose there are two balls: one steel ball that cannot break with a mass of 10 kg, and another smaller wooden ball with a mass of 1 kg, which will break if a force of 10 N is applied to it.
Consider ...
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How do i solve this current electricity problem? [closed]
Question: An engineer has access to a tetrahedron building block with side length 10 cm. The body is made of a thermal insulator but the edges are wrapped with a thin copper wiring with cross ...
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Problem explanation from Estonian-Finish Physics 2003 olympiad [closed]
I am having trouble understanding problem 5.3 (Vibrations) from the Estonian-Finish 2003 Physics olympiad. Specifically in 5.3 they say "brick is kept in motion along(horizontal) $y$-axis by a ...
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Could you please answer my questions (I have four questions)? [closed]
1.must the positive direction is always upwards when we study systems that have springs in a vertical way and we cannot assume that the positive direction is downwards?
If I understand correctly, how ...
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Minimum energy to be given to a swing for it to completely coil up around the main support bar [closed]
The question is the title. To find the minimum energy to be given to a swing for it to completely coil up around the main support bar.
Generalization, swing can be thought of as a single pendulum. By ...
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A question on modified flux function under perturbation [closed]
Given a magnetic field $\mathbf{B}=B_{0}\left(\dfrac{xz}{z_{s}^{2}},\dfrac{yz}{z_{s}^{2}}, 1-2\left( \dfrac{x^{2}}{r_{s}^{2}}+\dfrac{y^{2}}{r_{s}^{2}}\right) -\dfrac{z^{2}}{z_{s}^{2}}\right)$ with the ...
