Question regarding angular frequency of a SHM

AI Thread Summary
The discussion centers on the relationship between angular frequency (ω), kinetic energy (KE), and amplitude in simple harmonic motion (SHM). It clarifies that ω remains constant when the spring constant (k) and mass (m) are unchanged, despite variations in maximum KE and amplitude. Participants emphasize that changes in KE indicate a change in amplitude while maintaining the same oscillator conditions. The formula KE=½m(ωa)² is referenced to illustrate how maximum KE is dependent on both ω and amplitude. Ultimately, the consistency of ω is affirmed due to the fixed parameters of the spring and mass in the system.
Janiceleong26
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1. Homework Statement

image.jpg

image.jpg

Homework Equations


KE=½m(ωa)2

The Attempt at a Solution


So first I did this:
2.4x10-3= ½ mω2(1.5x10-2)2
To find mω2=21.33
And substitute that into the KE eqn to find the new amplitude, which is 1.30x10-2
But I only did that because that was the only way I could think of.
My question is, why is ω constant despite changes in the max KE?
 
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Janiceleong26 said:
1. Homework Statement

View attachment 98703
View attachment 98704

Homework Equations


KE=½m(ωa)2

The Attempt at a Solution


So first I did this:
2.4x10-3= ½ mω2(1.5x10-2)2
To find mω2=21.33
And substitute that into the KE eqn to find the new amplitude, which is 1.30x10-2
But I only did that because that was the only way I could think of.
My question is, why is ω constant despite changes in the max KE?
How does the max KE depend on ω and the amplitude?
 
Linear velocity will change during the oscillation (x changes)
upload_2016-4-7_10-57-15.png


so the KE

upload_2016-4-7_10-59-52.png


will too:
upload_2016-4-7_10-58-50.png
 

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ehild said:
How does the max KE depend on ω and the amplitude?
Max KE=½m(ωa)2
 
@Physics-Tutor Thanks but I'm still confused. How do we know that the angular frequency, ω, is constant?
 
Janiceleong26 said:
Max KE=½m(ωa)2
Changing KE means changing the amplitude if it is the same oscillator. You know that ω=√(k/m). If the spring is the same and the mass of the load is the same, why should the frequency change?
 
Janiceleong26 said:
@Physics-Tutor Thanks but I'm still confused. How do we know that the angular frequency, ω, is constant?
We use the same spring and loading mass.
 
Janiceleong26 said:
Thanks but I'm still confused. How do we know that the angular frequency, ω, is constant?
ehild said:
We use the same spring and loading mass.
ehild is correct:
upload_2016-4-7_14-11-33.png


k is the spring constant, m the mass. These two are constant, so the angular velocity is constant.
 

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ehild said:
Changing KE means changing the amplitude if it is the same oscillator. You know that ω=√(k/m). If the spring is the same and the mass of the load is the same, why should the frequency change?
Physics-Tutor said:
ehild is correct:
View attachment 98717

k is the spring constant, m the mass. These two are constant, so the angular velocity is constant.
Oh, I got it. Thanks a lot !
 
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