Help with Potential Energy Curve question

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The discussion revolves around a problem involving a conservative force acting on a particle, with a focus on analyzing its potential energy curve. Participants clarify that the derivative of the potential energy graph represents the force acting on the particle, which aids in determining its magnitude and direction. The limits of motion for the particle are identified as the points where it oscillates, linked to the potential energy well concept. Calculating the particle's energy and understanding its behavior in the potential well are emphasized as key steps in solving the problem. Overall, the conversation highlights the importance of interpreting the graph and applying relevant physics equations to find the answers.
Caps1394
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Homework Statement


A conservative force F(x) acts on a 3.0 kg particle that moves along the x axis. The potential energy U(x) associated with F(x) is graphed in Figure 8-60. When the particle is at x = 3.0 m, its velocity is -1.0 m/s. The "kinks" in the graph occur at (1, -2.8), (4, -17.2), and (8.5, -17.2); and the endpoint is at (15, -2).
08_49.gif

(a) What are the magnitude and direction of F(x) at this position?
Magnitude
(b) Between what limits of x does the particle move?
Lower limit and and upper limit
(c) What is its speed at x = 7.0 m?

Homework Equations


Ke=1/2MV2


The Attempt at a Solution


I'm not even sure how to start this problem
 
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What does the derivative or slope on the graph represent? That should give you a good start!
 
That was easy enough!

But about the limits. Would the lower and upper limits be the points where the particle oscillates between?
 
Caps1394 said:
That was easy enough!

But about the limits. Would the lower and upper limits be the points where the particle oscillates between?
Apparently, you've answered this question to yourself. It will be hard to help you if you don't respond with the answer and why or how you came up with that answer.
 
"Would the lower and upper limits be the points where the particle oscillates between?"

Yes. This part is a bit complicated but your use of "oscillates" indicates you know what is going on. Kind of like an atom in the potential well of a molecule. Just a matter of calculating the energy it has and using the graph, I think.
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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