Time in brachistochrone problem

Using the parametric equations for x and y, we can substitute this into the time equation and integrate to find the minimum time needed for the ball to travel from point 1 to point 2. This time is represented by t_{12}.
  • #1
hriby
3
0
I hope that you've heard about Brachistochrone problem: http://mathworld.wolfram.com/BrachistochroneProblem.html
Given two points, I can find (calculate) the courve, on which the ball needs minimum time to travel from point 1 to point 2.
I get the equation for the courve, which is cycloid, in parametric form, let say:
[tex]
x(\theta)&=&C\left(\theta-\sin{\theta}\right),
[/tex]

[tex]
y(\theta)&=&-C\left(1-\cos{\theta}\right).
[/tex]

Now I also need to calculate the time needed...
How could I calculate it out of formula below using the equation for the courve/cycloid in parametric form?
[tex]t_{12}=\int_{T_1}^{T_2} \frac{\sqrt{1+{y'}^2}}{\sqrt{2g\,y}}dx, \quad y'=\frac{dy}{dx}[/tex]
Thanks for your answers!
Hriby
 
Last edited:
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  • #2
how 'bout:

dy/dx = (dy/d_theta)/(dx/d_theta)
 

Related to Time in brachistochrone problem

1. What is the brachistochrone problem?

The brachistochrone problem is a physics problem that involves finding the path of shortest time between two points in a gravitational field. It was first proposed by Johann Bernoulli in 1696 and is considered one of the earliest problems in the calculus of variations.

2. How is time related to the brachistochrone problem?

Time is a crucial factor in the brachistochrone problem, as it is the measure of how long it takes for an object to travel along the path between two points. The goal of the problem is to find the path that minimizes the time it takes for the object to travel between the two points.

3. What is the significance of the brachistochrone problem?

The brachistochrone problem is significant because it demonstrates the power of the calculus of variations in solving complex problems. It also has practical applications in fields such as engineering and physics, where minimizing travel time is important.

4. How is the brachistochrone problem solved?

The brachistochrone problem is typically solved using the principle of least action, which states that the path taken by an object between two points is the one that minimizes the action (the integral of energy over time). This can be solved using the Euler-Lagrange equations.

5. Are there real-life examples of the brachistochrone problem?

Yes, there are many real-life examples of the brachistochrone problem, including the path taken by a roller coaster to minimize the time it takes to reach the end of the track, the trajectory of a spacecraft to reach a certain destination in the shortest time, and the path taken by a light beam to travel between two points in a medium with varying refractive indices.

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