Motion of point when sound volume goes up

Click For Summary
SUMMARY

The discussion centers on the physics of sound production by a radio speaker's diaphragm, specifically addressing the relationship between sound volume and diaphragm motion. When the volume increases, both the maximum displacement and the average speed of the diaphragm increase, confirming that option c) is correct. The increase in loudness correlates with greater amplitude, which directly affects the diaphragm's motion, despite the frequency remaining constant. Understanding this relationship is crucial for solving AP Physics 1 problems related to sound waves.

PREREQUISITES
  • Understanding of sound wave properties, including amplitude and frequency.
  • Familiarity with basic physics concepts such as displacement and speed.
  • Knowledge of the relationship between sound volume and diaphragm motion.
  • Ability to apply equations related to wave motion, such as v = f * λ.
NEXT STEPS
  • Study the relationship between amplitude and sound intensity in acoustics.
  • Learn about the mechanics of diaphragm motion in speakers and other sound-producing devices.
  • Explore the concept of wave speed versus membrane speed in sound production.
  • Review AP Physics 1 sample problems related to wave motion and sound.
USEFUL FOR

This discussion is beneficial for AP Physics students, educators teaching sound wave concepts, and anyone interested in the mechanics of sound production in speakers.

JessicaHelena
Messages
188
Reaction score
3

Homework Statement


A radio speaker produces sound when a membrane called a diaphragm vibrates, as shown above. A person turns up the volume on the radio. Which of the following aspects of the motion of a point on the diaphragm must increase?

a) the max. displacement only
b) the average speed only
c) both a) and b)
d) neither a) nor b)

(This is an AP Physics 1 sample problem)

Homework Equations



v=f * lambda (?)

The Attempt at a Solution


I know that the displacement will increase bc a louder volume leads to a greater amplitude (which is the displacement). The answer says that the average speed too must increase (it is choice c), but I'm having a hard time understanding that: I thought that loudness — and so amplitude — has nothing to do with the speed.
 
Physics news on Phys.org
The frequency stays the same. How would you travel a larger distance in the same time without increasing the speed?

This is not the speed of the wave propagation (which stays constant). It is the speed of the membrane - much slower than the speed of sound.
 

Thread 'Magnitude of buoyant force in fluids of different densities'

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?
View full post »

Similar threads

Increase in the volume of a sound
  • · Replies 2 ·
Replies
2
Views
1K
Sound Wave Interference and Finding the Path Differences with Diagrams
  • · Replies 20 ·
Replies
20
Views
5K
Audio interference of sound waves from two speakers
  • · Replies 19 ·
Replies
19
Views
4K
What is the power of a sound source placed on a tall radio tower?
  • · Replies 1 ·
Replies
1
Views
2K
Sound Wave Interference Problem
  • · Replies 5 ·
Replies
5
Views
2K
Instantaneous Displacement of a Sound Wave
  • · Replies 2 ·
Replies
2
Views
10K
Constructive interference with sound -- word problem
  • · Replies 15 ·
Replies
15
Views
3K
Are These Physics Questions Correct in English and Science?
  • · Replies 6 ·
Replies
6
Views
2K
Distance needed to walk in order to hear local maximum
  • · Replies 27 ·
Replies
27
Views
4K
Sound of vibrating string - modes
  • · Replies 2 ·
Replies
2
Views
2K