What does the phase angle phi mean in the harmonic oscillation function?

In summary, the function for simple harmonic oscillation is Acos(ωT)+ϕ. The angle phi is added to determine the initial position of the oscillation. The frequency of the oscillation can be derived from the equation of force varying with negative displacement, where the constant is taken as the frequency. If phi has a value, the graph of the oscillation would change from sine to cosine. Phi only affects the initial position of the oscillation.
  • #1
CrazyNeutrino
100
0
The function for simple harmonic oscillation is:
Acos(ωT)+[itex]\phi[/itex]
Why is there an angle phi added to the function acos(ωT)?
 
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  • #2
it's Acos(ωT+ϕ) omega stands for how fast it' s oscilating, but phi determines the initial position( wold be Acosϕ)
 
  • #3
I was reading a book on wave and found that when they derive the equation of shm from the equation force varies with negetive displacement , they had taken a propotionality constant to make the force and displacement equal and they had taken frequency of the shm as the constant . So my question is , is there any derivation which can show that the constant is the frequency of the shm .
 
  • #4
If phi had a value, what would the shm graph look like? Or how would it change from Acos(wT)?
 
  • #5
CrazyNeutrino said:
If phi had a value, what would the shm graph look like? Or how would it change from Acos(wT)?
The graph would change from sine to cosine, (remember, that sin(x+π)=cosx)
 
  • #6
isnt the function already Acos(wT)+phi?
 
  • #7
so how could it change from sine if it doesn't start at sine?
 
  • #8
CrazyNeutrino said:
so how could it change from sine if it doesn't start at sine?
It never started as cosine, it's allways either sine or cosine or somethin in between. It's like you move the cosine a bit to the right and if you move it by π/2 you get sine! SO all phi determines is the initial position!
 
  • #9
Ok... Thanks! I almost understand.
 

1. What is the phase angle phi in the harmonic oscillation function?

The phase angle phi, denoted as Φ is a measure of the position of a harmonic oscillator at a given time. It represents the angular displacement of the oscillator from its equilibrium position.

2. How is the phase angle phi related to the amplitude and frequency in the harmonic oscillation function?

In a harmonic oscillation function, the phase angle phi is directly related to the amplitude and frequency of the oscillation. A change in the phase angle leads to a change in the amplitude and frequency of the oscillation.

3. How is the phase angle phi determined in a harmonic oscillation function?

The phase angle phi is determined by the initial conditions of the harmonic oscillator, such as its initial position and velocity. It can also be calculated using the equation Φ = arctan(v0/x0), where v0 is the initial velocity and x0 is the initial position.

4. What does a positive or negative phase angle phi indicate in a harmonic oscillation function?

A positive phase angle phi indicates that the harmonic oscillator is moving in the same direction as its initial position and velocity, while a negative phase angle indicates that the oscillator is moving in the opposite direction. This also affects the direction of the displacement and velocity of the oscillator at any given time.

5. Can the phase angle phi be changed in a harmonic oscillation function?

Yes, the phase angle phi can be changed by altering the initial conditions of the oscillator, such as its initial position and velocity. It can also be changed by applying external forces or changing the properties of the oscillator, such as its mass or spring constant.

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