Why the energy that waves transfer is only dependent on amplitude

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Discussion Overview

The discussion revolves around the relationship between wave energy transfer and amplitude, with participants exploring whether frequency also plays a significant role in energy transfer. The scope includes conceptual understanding of wave mechanics, particularly in the context of mechanical waves such as those on a rope and water waves.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions why wave energy transfer is said to depend only on amplitude, suggesting that faster waves might transfer more energy even with the same amplitude.
  • Another participant asserts that for a given wave in a medium, the speed is constant, and energy transfer is determined by amplitude, but acknowledges that increasing frequency leads to more disturbances in the medium, potentially increasing energy transfer.
  • A link is provided that discusses the relationship between wave frequency and power, implying that more cycles per second result in greater energy transfer.
  • Further inquiries are made about the role of frequency, with participants suggesting that higher frequency could lead to more energy being transferred.
  • One participant shares a textbook statement indicating that energy transfer to a boat from water waves is dependent on amplitude rather than frequency, which raises confusion among others.
  • Another participant notes that surface waves have different characteristics and may not follow the same rules as other types of waves, suggesting a need for clarity in the discussion.
  • Angular frequency is mentioned, with a participant confirming its relationship to wave frequency.

Areas of Agreement / Disagreement

Participants express differing views on the role of frequency in energy transfer, with some asserting that it is solely dependent on amplitude, while others argue that frequency also contributes to energy transfer. The discussion remains unresolved regarding the extent to which frequency impacts energy transfer in waves.

Contextual Notes

Participants reference different types of waves (e.g., surface waves, waves on strings, sound waves) and their unique properties, indicating that the discussion may be limited by the specific context of the waves being considered. There is also mention of potential confusion arising from textbook definitions that may not align with the participants' interpretations.

Karagoz
Hi,

I wonder why the energy that waves transfer is only dependent on amplitude?

E.g. in this animation:
http://lifecdn.dailyburn.com/life/wp-content/uploads/2015/02/2.Alternating-Slam4.gif

The waves on the rope transfer energy to the items on the right side.

Wouldn't there be transferred more energy if the man produced faster waves, but with same amplitude?

Or waves transfer energy to the boat on water (by moving the boat up and down).

Even if the amplitude of the water waves was the same, with faster waves, the boat would move more up and down than if the waves were slower.

So wouldn't the waves transfer more energy to the boat if the speed of the waves was faster, even when the amplitude is same?

(btw, I'm very very new to physics).
 
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Hey, i don't know if you know that or not, speed of the wave in a medium is constant for a given condition. So, for a given wave if frequency is constant then the wave transfer same energy for given amplitude. But if frequency increases then for the same time there will be more disturbance in the medium, so the energy transferred by that wave is more due to its frequency keeping the amplitude constant.
 
But what about frequency?

As higher the frequency, more will there be disturbance, hence more energy will be transferred?

Higher frequency in wave (not photons or light wave, but other waves) means more energy?
 
Karagoz said:
I wonder why the energy that waves transfer is only dependent on amplitude?

Is it? See the link sophiecentaur posted. It contains this equation..

powstr3.gif
 
Perhaps get a rope and try it out. Is it harder for you to shake the rope faster (eg at a higher frequency)?
 
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Is angular frequency is something similar to frequency of the wave, which is measured with Hertz?

This is what's written in physics textbook for students (translation):
"We know how water waves transfer energy to a boat. They put the boat into swings with same frequency as waves' frequency. How much energy the boat gets, is not dependent on the wave-frequency , but dependent on amplitude. Bigger the amplitude the waves have, higher the boat will get lift up, and thus more energy it will get. All waves, including sound waves too, transfer energy that way." (in later paragraphs it explains that photons and light waves work differently).

This is why I get confused.
 
Karagoz said:
"We know how water waves transfer energy to a boat.
Water ('surface') waves have a different formula for energy, speed and wavelength and they are not the best waves to discuss for a starter. It's best to sort out waves on strings or normal sound waves before getting involved with surface waves on fluids, which don't follow the normal rules.
 
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Good catch.
 
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  • #11
Karagoz said:
But what about frequency?

As higher the frequency, more will there be disturbance, hence more energy will be transferred?

Higher frequency in wave (not photons or light wave, but other waves) means more energy?
Yes, it means higher energy as long as you keep amplitude constant for the wave.
 

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