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3 votes
0 answers
46 views

Relating Brachistochrone problem to Fermat's principle of least time [closed]

When I came across the Brachistochrone problem, my teacher said we could relate it to Fermat's principle of least time. So, we could make many glass slabs of high $\mathrm dx$, and every slab has a ...
AANT's user avatar
  • 31
1 vote
1 answer
60 views

How to prove that the Brachistochrone problem could be reduced to finding a curve on a plane?

Given two points in space, the 2D Brachistochrone problem could be solved to give solution of a cycloid. I am wondering how could one prove that in arbitrary dimensions ($d\geq 3$) with a 1D uniform ...
Rescy_'s user avatar
  • 838
1 vote
0 answers
75 views

Inconsistency in solving the Brachistochrone Problem. Did I make a mistake? [closed]

Background: Equation of Motion Okay. First I want to see if my "Newtonian Mechanics" lens of the problem is correct. Let the particle's path be given by $\vec{r}(t) = (x(t), y(t))$ and just ...
Lendel Deguia's user avatar
3 votes
1 answer
123 views

What is the definition of a Brachistochrone curve in a non-Euclidean space?

I have a problem where I have to study "the geometric properties of the Brachistochrone curve in non-Euclidean spaces". But I am confused about the definition of the Brachistochrone Problem/...
Karl's user avatar
  • 31
0 votes
1 answer
102 views

For virtual displacement in the Lagrangian, why is $\delta \dot{x_i} = \delta \frac{dx_i}{dt} = \frac{d}{dt}\delta x_i \equiv 0$?

I am having trouble understanding why $$\delta \dot{x_i} = \delta \frac{dx_i}{dt} = \frac{d}{dt}\delta x_i \equiv 0.\tag{7.132}$$ you can see my explanation leading up to it below. I would greatly ...
Reuben's user avatar
  • 283
0 votes
0 answers
65 views

Hypocyloid Integral in Polar Coordinates

I've been working on the classic problem of finding the path through which a body travels in least time between two points on the surface of the Earth, assuming that the body is allowed to fall ...
deneb.algedi's user avatar
1 vote
1 answer
114 views

Brachistochrone Problem without Trigonometric Substitution

I'm trying to numerically reproduce the cycloid solution for the brachistochrone problem. In doing so, I eventually ended up with the following integral: $$ x = \int{\sqrt{\frac{y}{2a-y}} dy} $$ ...
rb3652's user avatar
  • 165
0 votes
2 answers
120 views

Descent on an inclined wavy frictionless track [closed]

The classical Brachistochrone was actually counterintuitive wherein the time of descent is lesser (the least) for the cycloid than that of the corresponding straight inclined track. Let an inclined ...
Z Ahmed's user avatar
  • 103
5 votes
1 answer
426 views

Could two concatenated cycloids be an optimal solution to the Brachistochrone problem?

The following is a specific instance of the brachistochrone problem, which I first encountered in grad school, and I have occasionally used as hw problem in teaching CM. A particle is started from ...
Thomas's user avatar
  • 18.8k
3 votes
1 answer
190 views

Comparing Brachistochrone curve with a Hypocycloid curve

I want to compare the time that it takes to slide a particle in a frictionless hypocycloid curve, so time would be given by the arclength divided by the velocity So I need first compute the arclength ...
Oscar  Acevedo's user avatar
7 votes
1 answer
1k views

What shape of track minimizes the time a ball takes between start and stop points of equal height?

I was at my son's high school "open house" and the physics teacher did a demo with two curtain rail tracks and two ball bearings. One track was straight and on a slight slope. The beginning and end ...
Colin Warwick's user avatar
10 votes
1 answer
2k views

Brachistochrone Problem for Inhomogeneous Potential

This recent question about holes dug through the Earth led me to wonder: if I wanted to dig out a tube from the north pole to the equator and build a water slide in it, which shape would be the ...
Mark Eichenlaub's user avatar