What is phi? Understanding Conservative Forces

In summary, phi is the magnitude of the force vector and can be used to define the potential energy function U(\vec r) = -\int_0^r \phi(r') dr'. However, this equation is only valid for central forces and if the forces are not central, the equation will not hold regardless of the value of phi.
  • #1
Nusc
760
2
When you define [tex] \vec F(\vec r) = \phi(r') (\vec r)/r [/tex]
Now U is usually denoted

[tex] U(\vec r) = -\int_0^r \phi(r') dr'[/tex]

What is phi?
 
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  • #2
It would appear that phi is just the magnitude of the Force vector...

EDIT: after looking at it a bit more, I don't believe the first equation can be true in general. Since the only vector on the RHS is the r vector, that means this equation would only work for central forces. In that case, phi should indeed be the magnitude of the force vector. If the forces are not central forces...then you can't get the equation to hold no matter what you set phi to.
 
  • #3
Yeah they are central, thx.
 

FAQ: What is phi? Understanding Conservative Forces

1. What is phi?

Phi, also known as the golden ratio, is a mathematical constant that is approximately equal to 1.618. It is often denoted by the Greek letter Φ (phi) and has been studied and admired by mathematicians, artists, and scientists for centuries.

2. How is phi related to conservative forces?

In physics, conservative forces are those that conserve mechanical energy, meaning that the total energy of a system remains constant. Phi is often used to describe the relationship between conservative forces and the distance between two points in a system. Specifically, the golden ratio is found in the equations that describe the motion of objects under conservative forces.

3. How is phi calculated?

Phi can be calculated in a few different ways, but one of the most common methods is to use the quadratic equation x^2 = x + 1, which has a solution of x = Φ = (1 + √5)/2. This method is based on the fact that the ratio of two consecutive numbers in the Fibonacci sequence (1, 1, 2, 3, 5, 8, 13, etc.) approaches phi as the numbers get larger.

4. What are some real-world examples of phi and conservative forces?

There are many examples of phi and conservative forces in the real world. Some examples include the arrangement of seeds in a sunflower, the spiral growth pattern of nautilus shells, and even the shape of galaxies. In physics, common examples of conservative forces include gravity, electric and magnetic forces, and the force of a spring.

5. Why is phi important in science and mathematics?

Phi is important in science and mathematics because it appears in many natural phenomena and can be used to describe the behavior of complex systems. It has also been found to be aesthetically pleasing and has been used in art and design for centuries. Additionally, phi and conservative forces play a crucial role in understanding the fundamental laws of physics and the behavior of matter and energy in the world around us.

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