"In #CelestialMechanics, the #LagrangePoints (/lə.ˈɡrɑːndʒ/; also #Lagrangian points or #Libration points) are points of equilibrium for small-mass objects under the gravitational influence of two #MassiveOrbitingBodies. Mathematically, this involves the solution of the #RestrictedThreeBodyProblem."

A cycloidal pendulum - one suspended from the cusp of an inverted cycloid - is isochronous, meaning its period is constant regardless of the amplitude of the swing. Please find the proof using energy methods: Lagrange's equations (in the images attached to the reply).

Background:
The standard pendulum period of \(2\pi\sqrt{L/g}\) or frequency \(\sqrt{g/L}\) holds only for small oscillations. The frequency becomes smaller as the amplitude grows. If you want to build a pendulum whose frequency is independent of the amplitude, you should hang it from the cusp of a cycloid of a certain size, as shown in the gif. As the string wraps partially around the cycloid, the effect decreases the length of the string in the air, increasing the frequency back up to a constant value.

In more detail:
A cycloid is the path taken by a point on the rim of a rolling wheel. The upside-down cycloid in the gif can be parameterized by \((x, y)=R(\theta-\sin\theta, -1+\cos\theta)\), where \(\theta=0\) corresponds to the cusp. Consider a pendulum of length \(L=4R\) hanging from the cusp, and let \(\alpha\) be the angle the string makes with the vertical, as shown (in the proof).

#Pendulum #Cycloid #Period #Frequency #SHM #TimePeriod #CycloidalPendulum #Lagrange #Cusp #Energy #KineticEnergy #PotentialEnergy #Lagrangian #Length #Math #Maths #Physics #Mechanics #ClassicalMechanics #Amplitude #CircularFrequency #Motion #Vibration #HarmonicMotion #Parameter #ParemeterizedEquation #GoverningEquations #Equation #Equations #DifferentialEquations #Calculus

https://youtu.be/qqjlcuEHUlg

#Quantum #computation from #spacetime defect #networks | #MargaritaDavydova (#Caltech)

“Recorded as part of the Generalized Symmetries: #HighEnergy, #CondensedMatter and #Mathematics KITP conference from Apr 7, 2025 - Apr 10, 2025 at the Kavli Institute for #TheoreticalPhysics on the #UCSantaBarbara campus.”

#UCSB
#physics #computing #qubits #topologicaldefects #lagrangian

more at: https://www.kitp.ucsb.edu/activities/gensym-c25

Quantum computation from spacetime defect networks | Margarita Davydova (Caltech)

YouTube
Glauert's optimum rotor disk revisited – a calculus of variations solution and exact integrals for thrust and bending moment coefficients

Abstract. The present work is an amendment to Glauert's optimum rotor disk solution for the maximum power coefficient, CPmax, as a function of tip speed ratio, λ. First, an alternate mathematical approach is pursued towards the optimization problem by means of calculus of variations. Secondly, analytical solutions for thrust and bending moment coefficients, CT and CBe, are derived, where an interesting characteristic is revealed pertaining to their asymptotic behavior for λ→∞. In addition, the limit case of the non-rotating actuator disk for λ→0 is shown for all three performance coefficients by repeated use of L'Hôpital's theorem, and its validity is discussed in the context of other works since Glauert.

How Noether’s Theorem Revolutionized Physics | Quanta Magazine

Emmy Noether showed that fundamental physical laws are just a consequence of simple symmetries. A century later, her insights continue to shape physics.

Quanta Magazine

Tracking Ice Floes

To understand why some sea ice melts and other sea ice survives, researchers tracked millions of floes over decades. This herculean undertaking combined satellite data, weather reports, and buoy data into a database covering nearly 20 years of data. With all of that information, the team could track the changes to specific pieces of ice rather than lumping data into overall averages.

They found that an ice floe’s fate depended strongly on the route it took: ice that slipped from its starting region into warmer, more southern regions was likely to melt. They also saw region-specific effects, like that thick sea ice was more likely to melt in the East Siberian Sea’s summer, possibly due to warmer currents. The comprehensive, fine-grained analyses possible with this ice-tracking technique offer a chance to understand why some Arctic regions are more vulnerable to warming than others. (Image credit: D. Cantelli; research credit: P. Taylor et al.; via Eos)

#climateChange #Eulerian #fluidDynamics #Lagrangian #melting #physics #planetaryScience #science #seaIce

The influence of sea ice drift on sea ice survivability

The state of Arctic sea ice influences aspects of many global systems including...

AGU - AGU24

New #python #physics video - building a 3D animation of a half-atwood with a spring using #Lagrangian mechanics and #sympy (of course #vpython too)

https://youtu.be/wB_hs-Dhs3c

Python Physics: Building a Lagrangian Model for a Half Atwood with Spring

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New #physics #lagrangian - flinging a bead from a rotating stick. Yes, of course there is a #python model. Do you not even know me?

https://youtu.be/IqRaVK5lQ5g

Lagrangian Mechanics: Bead on a Pivoting Wire. Bonus: What Happens When it Flings Off the End?

This is part of my classical mechanics series. You can find all my videos in the series in the following playlist.https://www.youtube.com/playlist?list=PLWFl...

YouTube

New #physics #classicalmechanics video - a mass slides down a frictionless parabola. Will it ever lose contact with the surface? Solved using #lagrangian and #python

https://youtu.be/DF6ixJakMDU

Lagrangian Mechanics: Would a Block Fall Off a Parabolic Path?

YouTube

New #physics video - using Lagrange Multipliers to find forces of constraint.
#classicalmechanics #lagrangian

https://youtu.be/CLckOYdTZyo

Lagrangian Mechanics: Using Lagrange Multipliers to Find Forces of Constraint

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