1 / 19

Understanding Electric Potential Energy in Physics

Learn how electric potential energy is defined as the negative work done by an electric field, and its relation to Coulomb force. Discover the scalar sum of potential energies and calculations involving point charges. Explore examples and concepts in physics.

jpendergrass
Download Presentation

Understanding Electric Potential Energy in Physics

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Physics 212 Lecture 5 Today's Concept: Electric Potential Energy Defined as Minus Work Done by Electric Field

  2. Main Point 1 First, the Coulomb force is a conservative force. By that, we mean that the work done by the Coulomb force on a charged particle as it is moved between any two points is independent of the path taken between those two points.

  3. Main Point 2 Second, since the Coulomb force is a conservative force, we can define an electric potential energy associated with this force. In particular, we defined the change in electric potential energy of a charged particle moved from point A to point B to be minus the work done by the Coulomb force on that particle as it moves between the two points.

  4. Main Point 3 Third, the electric potential energy of a system of fixed charged particles is just equal to the scalar sum of the electric potential energies due to each pair of particles.

  5. F W Object speeds up ( DK > 0 ) dr F dr or W Object slows down ( DK < 0 ) F dr F W Constant speed ( DK = 0 ) dr Recall from physics 211:

  6. Example: Two Point Charges Calculate the change in potential energy for two point charges originally very far apart moved to a separation of “d” d q1 q2 For point charges often choose r=infinity as “zero” potential energy.

  7. Potential Energy of Many Charges d q d Two charges are separated by a distance d. What is the change in potential energy when a third charge q is brought from far away to a distance d from the original two charges? Q2 d Q1

  8. Checkpoint 1 A B C D E 34

  9. Checkpoint 2 A B C D 31

  10. Checkpoint 3 34

  11. Checkpoint 4 A charge is released from rest in a region of electric field. The charge will start to move A) in a direction that makes its potential energy increaseB) in a direction that makes its potential energy decreaseC) along a path of constant potential energy 34

  12. Example A positive charge q is placed at x=0 and a negative charge -2q is placed at x=d. At how many different places along the x axis could another positive charge be placed without changing the total potential energy of the system? -2q q x X=0 X=d 40

More Related