Understanding Potential Energy and Force for a Constant Potential Function

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SUMMARY

The potential energy function is defined as U = C/x, where C is a positive constant. The force as a function of x can be derived using the relationship F = -dU/dx, resulting in F = -C/x². This force is directed toward the origin when C is positive, indicating an attractive force. If C is negative, the potential energy decreases as x increases, leading to a repulsive force directed away from the origin.

PREREQUISITES
  • Understanding of potential energy and force relationships in physics
  • Knowledge of calculus, specifically differentiation
  • Familiarity with conservative forces and work-energy principles
  • Basic grasp of integral calculus for potential energy calculations
NEXT STEPS
  • Study the derivation of force from potential energy using F = -dU/dx
  • Explore the implications of negative constants in potential energy functions
  • Learn about conservative forces and their characteristics in physics
  • Investigate applications of potential energy in different physical systems
USEFUL FOR

Students studying classical mechanics, physics educators, and anyone interested in the mathematical relationships between force and potential energy in conservative systems.

yamama1
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Homework Statement


Potential energy function is given by U = C/x, where C is a positive constant.
a. Find the force as a function of x.
b. Is this force directed toward the origin or away from it?
c. Does the potential energy increase or decrease as x increases?
d. Answer b, and c if C is a negative constant.

Homework Equations


How do you relate U = C/x to force?

The Attempt at a Solution


I tried the formulas.
F = mg
U = mgy
But I am not sure how you relate both of them together
 
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welcome to pf!

hi yamama1! welcome to pf! :wink:

potential energy is (minus) the work done by a (conservative) force

in other words, PE = -∫F.dx,

and so F = … ? :smile:

(see the pf library for some details)
 


tiny-tim said:
hi yamama1! welcome to pf! :wink:

potential energy is (minus) the work done by a (conservative) force

in other words, PE = -∫F.dx,

and so F = … ? :smile:

(see the pf library for some details)


F = ma.
so PE = - ∫ma.
I don't know what that would equal to.
 
(just got up :zzz: …)
yamama1 said:
F = ma.
so PE = - ∫ma.
I don't know what that would equal to.

stick to the question … nobody's asked you for a

you're asked for F, you're given PE, and you have an equation relating PE and F …

so what is F (as a function of PE)? :smile:

(oh, and PE isn't -∫ma. it's -∫ma.dx = -∫mv(dv/dx)dx = -∫mvdv = -1/2 mv2)
 
apply F= -dU/dx
 

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