1 / 15

-Relating Conservative Force and Potential Energy -Energy diagrams and Equilibrium

-Relating Conservative Force and Potential Energy -Energy diagrams and Equilibrium. AP Physics C Mrs. Coyle. A Force is “Conservative” if:. “ the work this force does on an object that moves between two points depends only on the position of these two points and not on the path.”

jeffreydwyer
Download Presentation

-Relating Conservative Force and Potential Energy -Energy diagrams and Equilibrium

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. -Relating Conservative Force and Potential Energy-Energy diagrams and Equilibrium AP Physics CMrs. Coyle

  2. A Force is “Conservative” if: • “ the work this force does on an object that moves between two points depends only on the position of these two points and not on the path.” • “the work this force does on an object that moves through a round trip is zero.” • Example: gravity, force of a spring.

  3. Consider a ball thrown up and the system is the ball and the earth. • The work done by the force of gravity Wg =-ΔU

  4. For a particle moving along the x-axis (one dimensional motion)while a conservative force, in the same axis, within the system acts on it: ΔU is the change in potential energy of the system

  5. Solving for Fx:

  6. Example: Find the gravitational force for a particle a distance x above the earth’s surface. • Start with U= mgx • Find F

  7. Example: Find the spring force for a particle attached to a spring: • Start with U= ½ kx2 • Find F(x):

  8. Types of Positions of Equilibrium • Stable Equilibrium: movement away from this (x=0) position results in a restoring force. • Unstable Equilibrium: movement away from this position results in a force directed away from x=0 • Neutral equilibrium: movement away from x=0 does not result in either restoring nor disruptive forces.

  9. Energy Diagrams, U(x) vs x

  10. -Energy Diagrams -U(x) is minimum at x=0 (stable equilibrium) xmax and –xmax : turning points

  11. Unstable equilibriumU(x) is max

  12. Neutral EquilibriumU(x) is constant

  13. Example 1 (#40) A single conservative force acting on a particle varies as F=(-Ax+Bx2 )i N, where A and B are constants and x is in meters. a) Calculate the potential energy function taking U=0 at x=0 b) Find the change in potential energy and change in kinetic energy as the particle moves from x=2.00m to x=3.00m

  14. Example 2 (#42) • A potential energy function for a two dimensional force is U=3x3y - 7x • Find the force that acts at the point (x, y) • Hint find F(x) and F(y).

More Related