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1 vote
0 answers
48 views

Find curve minimizing energy loss due to friction [closed]

I am looking for an ansatz of the following problem: Given a mass $m$ moving in a constant gravitational field along curves $C$ connecting two fixed points I want to find the curve $C_0$ that ...
TomS's user avatar
  • 917
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
2 votes
2 answers
273 views

Brachistochrone to a vertical line [closed]

Just for fun, I am working through some problems in Mathematics of Classical and Quantum Physics by Byron and Fuller. Problem 2.13 reads: Prove that a particle moving under gravity in a plane from a ...
OmnipotentEntity's user avatar
3 votes
3 answers
428 views

Lagrangian Derivation of Brachistocrone? [closed]

I've been trying to derive the functional description of the brachistocrone. To do this, I used the Lagrangian to describe motion along a functional path. given a function $ f(x) $ where $0<y<a$ ...
BooleanDesigns's user avatar