Energy Transport and the Amplitude of a Wave
If the specimen vibrates with amplitude of only a few nanometers, it will be impossible to see! The force varies harmonically, with amplitude and frequency . phenomenon of muscles is called the creep compliance. But the force applied does not necessarily vary with the EMG amplitude as in Fig Regression. discuss the parameters and the relations among them step by step in the Principles of Dynamic Atomic Force Microscopy I (Amplitude Modulation).
Pressure fluctuations caused by sound waves are much easier to measure. Animals including humans have been doing it for several hundred million years with devices called ears. Humans have also been doing it electromechanically for about a hundred years with devices called microphones. All types of amplitudes are equally valid for describing sound waves mathematically, but pressure amplitudes are the one we humans have the closest connection to.
In any case, the results of such measurements are rarely ever reported. Instead, amplitude measurements are almost always used as the raw data in some computation. When done by an electronic circuit like the circuits in a telephone that connect to a microphone the resulting value is called intensity.
When done by a neuronal circuit like the circuits in your brain that connect to your ears the resulting sensation is called loudness.
The intensity of a sound wave is a combination of its rate and density of energy transfer. It is an objective quantity associated with a wave.
Trunk muscle amplitude-force relationship is only quantitatively influenced by control strategy.
Loudness is a perceptual response to the physical property of intensity. It is a subjective quality associated with a wave and is a bit more complex. As a general rule the larger the amplitude, the greater the intensity, the louder the sound.
Sound waves with large amplitudes are said to be "loud". Sound waves with small amplitudes are said to be "quiet" or "soft".
What if one is made of zinc and the other is made of copper? Will the amplitudes now be the same or different? If a pulse is introduced into two different slinkies by imparting the same amount of energy, then the amplitudes of the pulses will not necessarily be the same. In a situation such as this, the actual amplitude assumed by the pulse is dependent upon two types of factors: Two different materials have different mass densities. The imparting of energy to the first coil of a slinky is done by the application of a force to this coil.
More massive slinkies have a greater inertia and thus tend to resist the force; this increased resistance by the greater mass tends to cause a reduction in the amplitude of the pulse. Different materials also have differing degrees of springiness or elasticity. A more elastic medium will tend to offer less resistance to the force and allow a greater amplitude pulse to travel through it; being less rigid and therefore more elasticthe same force causes a greater amplitude.
Dynamics and Vibrations: Notes: Forced Vibrations
Energy-Amplitude Mathematical Relationship The energy transported by a wave is directly proportional to the square of the amplitude of the wave. This energy-amplitude relationship is sometimes expressed in the following manner. This means that a doubling of the amplitude of a wave is indicative of a quadrupling of the energy transported by the wave. A tripling of the amplitude of a wave is indicative of a nine-fold increase in the amount of energy transported by the wave.
And a quadrupling of the amplitude of a wave is indicative of a fold increase in the amount of energy transported by the wave. The table at the right further expresses this energy-amplitude relationship.
Observe that whenever the amplitude increased by a given factor, the energy value is increased by the same factor squared. For example, changing the amplitude from 1 unit to 2 units represents a 2-fold increase in the amplitude and is accompanied by a 4-fold 22 increase in the energy; thus 2 units of energy becomes 4 times bigger - 8 units.
As another example, changing the amplitude from 1 unit to 4 units represents a 4-fold increase in the amplitude and is accompanied by a fold 42 increase in the energy; thus 2 units of energy becomes 16 times bigger - 32 units.
Re-evaluation of the amplitude-force relationship of trunk muscles.
Earthquakes and other geologic disturbances sometimes result in the formation of seismic waves. Seismic waves are waves of energy that are transported through the earth and over its surface. Earthquakes are given a Richter scale rating that indicates how intense the earthquake is. Use the Earthquake Energy widget below to explore the relationship between the Richter scale magnitude and the amount of energy transmitted by seismic waves.
Intensity – The Physics Hypertextbook
Check Your Understanding 1. Mac and Tosh stand 8 meters apart and demonstrate the motion of a transverse wave on a snakey. The wave can be described as having a vertical distance of 32 cm from a trough to a crest, a frequency of 2.