Loading in 5 sec....

-Relating Conservative Force and Potential Energy -Energy diagrams and EquilibriumPowerPoint Presentation

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

- 54 Views
- Uploaded on

Download Presentation
## PowerPoint Slideshow about ' -Relating Conservative Force and Potential Energy -Energy diagrams and Equilibrium' - todd-rosa

**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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript

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

AP Physics CMrs. 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.”
- “the work this force does on an object that moves through a round trip is zero.”
- Example: gravity, force of a spring.

Consider a ball thrown up and the system is the ball and the earth.

- The work done by the force of gravity Wg =-ΔU

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

Solving for F motion)while a conservative force, in the same axis, within the system acts on it:x:

Example: Find the gravitational force for a particle a distance x above the earth’s surface.

- Start with U= mgx
- Find F

Example: Find the spring force for a particle attached to a spring:

- Start with U= ½ kx2
- Find F(x):

Types of Positions of Equilibrium spring:

- 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.

Energy Diagrams, U(x) vs x spring:

-Energy Diagrams spring:-U(x) is minimum at x=0 (stable equilibrium)

xmax and –xmax :

turning points

Unstable equilibrium spring:U(x) is max

Neutral Equilibrium spring:U(x) is constant

Example 1 (#40) spring:

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

Example 2 (#42) spring:

- 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).

Download Presentation

Connecting to Server..