Potential Engery as a Function of X

In summary, when dealing with physics problems involving work, energy, and power, it is important to understand the relationship between potential energy and conservative forces. Taking the derivative of a potential energy function helps to determine equilibrium points, where the force is zero, and whether the equilibrium is stable or unstable. This can be helpful in solving problems and understanding the underlying principles of physics.
  • #1
muna580
I am doing my homewrok which relates to Work/Engery/Power stuff. Well, I came along this question and I didn't understand how to do it. I went to my book, and the book had the exact example of this problem. The book said to take the derivitive of this function and set it equal to 0 and solve for x. I did that and put in the answern and I got the answr right. :cool:

As a good student, wanting to learn and understand phsyics, I wanted to undertand why I would take the derivitive of this function and set it equal to 0. Can someone please explain to me, but I don't really undertand how to do this problem.

So far, I know the following things

[tex] \Sigma W = - \Delta U [/tex]
[tex] \Sigma W = \Delta K [/tex]

[tex] \Delta K = \frac{1}{2}mv^2 - \frac{1}{2}mvo^2 [/tex]

http://img156.imageshack.us/img156/2515/untitled1zn0.jpg
 
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  • #2
muna580 said:
As a good student, wanting to learn and understand phsyics, I wanted to undertand why I would take the derivitive of this function and set it equal to 0. Can someone please explain to me, but I don't really undertand how to do this problem.

You may want to put similar questions in the same thread in the future.

Well, your book should contain the fact (and the explanation of it) that potential energy has a stationary value for the state of equilibrium.
 
  • #3
muna580 said:
help please
Some forces are called conservative forces because they have the property that if you move an object that is acted on by such a force, and then return it to its original position, the force that was acting does no net work. An example of such a force is gravity. The force a spring exerts on an object is another. For all such forces, you can calculate the potential energy associated with the force by calculatiing the work done against the force to change the position of the object. For gravity, the force is -mg (downward). To raise an object from y = 0 to y = h requires that you do work against gravity of F*h = mgh. This calculation is really a very simple integral starting with

dW = Fdy

Integrating gives

W = Fy = mgy because the force is constant.

A derivative is the inverse operation to an integral. In fact, the indefinite integral is often called an antiderivative. If potential energy is found by integrating a force over a distance, it follows that if you know the potential energy you can find the force related to that potential energy by taking the derivative of the potential energy with respect to distance. For gravity F = -d(mgy)/dy = -mg(dy/dy) = -mg. The - sign comes in because potential energy is the work done against the force related to the potential energy, which is the opposite of the force itself.

Any point where the derivative of the potential energy is zero is a point where the force related to that potential energy is zero. It is an equilibrium point. If the derivative at nearby points (or the second dervivative) indicate that the point is a minimum in the potential energy, then the force is toward the equilibrium point and the equilibrium is stable. If the object is given a small displacement it is attracted back toward the equilibrium point. If the derivatives nearby indicate that the point is a maximum in the potential energy, the equilibrium is unstable and a slight displacement will cause the object to be pushed away.
 
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1. What is potential energy as a function of X?

Potential energy as a function of X is a mathematical representation of the change in potential energy of a system as a variable X changes. It describes how the potential energy of a system varies with changes in X.

2. How is potential energy as a function of X calculated?

The calculation of potential energy as a function of X depends on the specific system and the type of potential energy being considered. In general, it involves determining the potential energy at different values of X and creating a mathematical relationship between the two.

3. What types of systems can be described by potential energy as a function of X?

Any system that has potential energy and experiences changes in that energy as a function of a variable X can be described by this concept. Examples include a mass on a spring, a pendulum, or a charged particle in an electric field.

4. How is potential energy as a function of X used in science?

Potential energy as a function of X is used in various scientific fields, such as physics, chemistry, and engineering. It helps scientists understand and predict the behavior of systems and allows for the calculation of important parameters such as stability and equilibrium.

5. What is the significance of potential energy as a function of X?

Potential energy as a function of X is a fundamental concept in the study of energy and its role in physical systems. It allows for the quantitative analysis of energy changes and plays a crucial role in understanding the behavior of complex systems in nature.

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