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1 vote
0 answers
35 views

How to accurately average a function with a nonlinear response?

I am a physics PhD student working in optics and I have a bit of a weird problem that I am trying to sort out and I'm hoping you math folks can help me with. Without boring you with the experimental ...
UltrashortGiraffe's user avatar
4 votes
0 answers
170 views

Dynamics of a sliding cube on the $XY$ and $YZ$ planes

A cube with side length $a$, is initially placed with one vertex at the origin, and its faces parallel to the coordinate planes ($XY, XZ, YZ$) and totally lying in the first octant. Then its rotated ...
Quadrics's user avatar
  • 24.4k
0 votes
1 answer
597 views

Dimensionless form of the ODE for a simple pendulum with forcing and damping

I'm tasked with analysing the behaviour of a simple pendulum with driving and damping, which has the equation of motion: $$mL^{2}\ddot{\theta} + k\dot{\theta} + mgL\sin{\theta} = FL\cos{\Omega}t$$ For ...
vesbe1998's user avatar
0 votes
2 answers
173 views

Understanding Uniqueness of solutions of differential equations - nonlinear ODEs - pendulum example

Understanding Uniqueness of solutions of differential equations - nonlinear ODEs - pendulum example I am trying to understand If the nonlinear ODE of the classical equation for the pendulum with ...
Joako's user avatar
  • 1,534
5 votes
0 answers
221 views

What are the solutions for $y(t)\cdot\left(y'(t) + a\right)=-b\sin(t)$?

What are the solutions for $y(t)\cdot\left(y'(t) + a\right)=-b\sin(t)$? It could be proben that there exists some solutions? Are these solutions unique? and obviously, which are these solutions? (...
Joako's user avatar
  • 1,534
3 votes
1 answer
150 views

It is possible for a scalar finite-duration continuous system to achieve an infinite speed (in finite-time)? How if true? Why not if false?

It is possible for a scalar finite-duration continuous system to achieve an infinite speed (in finite-time)? How if it true? Why not if it false? (Please read first the restrictions of the system I am ...
Joako's user avatar
  • 1,534
0 votes
1 answer
105 views

Tilting a mass suspended on 2 springs

I was trying to model the following problem: There is a solid brick shaped body, with center of mass $(x,y,z)$. We put this body onto 2 springs. For making the problem easier, we cut out the slice ...
Shirohime Hajikuji's user avatar
1 vote
1 answer
34 views

Continuous dependence of duffing oscillator solution on forcing term

Consider the Duffing oscillator $\ddot{x} + 2 \gamma \rho \dot{x} + \rho^2 (\dot{x} + \alpha x^3) = F(t)$ for some forcing term $F(t)$. Are there any results that state that $x$ depends continuously ...
Tomas Jorovic's user avatar
1 vote
1 answer
33 views

A particle falling in a resisting medium. Solution to differential eqn of motion.

The particle is falling down, and $x$ is measured in down direction. $$x''=g-kv^4 \\ \implies\quad v\frac{dv}{dx}=g-kv^4$$ Solving this I get $$\frac{1}{4\sqrt{gk}}\log\bigg(\frac{\sqrt k v^2-\sqrt ...
Sonal_sqrt's user avatar
  • 4,711
3 votes
1 answer
84 views

How to find out the critical angle of a ball separating the circle?

Question: Let function $x:\mathbf R_+\to[0,2\pi]$ satisfying the second-order nonlinear ODE \begin{equation} \left\{ \begin{aligned} \ddot x(t) &= \sin x(t)-\cos x(t)+{\dot x(t)}^2, \quad t>0;...
Dreamer's user avatar
  • 1,972