Difference between two harmonic motion equations

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The discussion clarifies the differences between two harmonic motion equations: x(t)=Asin(ωt+φ) describes simple harmonic motion, indicating displacement over time, while y(x,t)=Asin(kx-ωt) represents a traveling wave moving in the +x direction, showing displacement at a specific position and time. The first equation focuses on the oscillation of a body from its equilibrium position, while the second emphasizes wave propagation. The confusion arises from their similar forms but distinct applications in physics. Understanding these differences is crucial for applying the equations correctly in real-life scenarios.
Rorshach
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Homework Statement


Hello, folks:) I'm currently having problem with properly understanding the difference and aplications of two equations which resemble each other greatly, but the difference makes it difficult for me to tell exactly which one is for what.

2. Homework Equations

Those two equations are given below:
(1) x(t)=Asin(ωt+φ)
(2) y(x,t)=Asin(kx-ωt)

The Attempt at a Solution


I know it is silly, but it's like I have brick wall in my mind that just prevents me from getting it right.
My initial conclusions told me that first one describes dependence of displacement of a body(in my particular case I was interested in acoustic wave) from beginning of coordinates system from time. Second one describes displacement of a body on axis perpendicular to the axis of direction of propagation of a wave I am interested in (in the dircetion of an amplitude, so to speak). Now I am just confused, and cannot place my conclusions in any real life illustrations. Please help me in getting this right.
 
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Rorshach said:
Those two equations are given below:
(1) x(t)=Asin(ωt+φ)
(2) y(x,t)=Asin(kx-ωt)
The second equation describes a traveling wave moving in the +x direction with some speed. y is the displacement of the wave at some position x and some time t.

The first equation can be used to describe the displacement of something in simple harmonic motion, where x is the displacement from equilibrium.

Let me know if that helps.
 
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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