Human ears can hear sound waves that vibrate in the range from about 20 times a second (a deep rumbling noise) to about 20,000 times a second (a high-pitched whistling). (Children can generally hear higher-pitched sounds than their parents, because our ability to hear high frequencies gets worse as we get older.) Speaking more scientifically, we could say that the sounds we can perceive have a frequency ranging from 20–20,000 hertz (Hz). A hertz is a measurement of how often something vibrates and 1 Hz is equal to one vibration each second. The human voice makes sounds ranging from a few hundred hertz to a few thousand hertz.Suppose you could somehow hit a drum-skin so often that it vibrated more than 20,000 times per second. You might be able to see the skin vibrating (just), but you certainly couldn't hear it. No matter how hard you hit the drum, you wouldn't hear a sound. The drum would still be transmitting sound waves, but your ears wouldn't be able to recognize them. Bats, dogs, dolphins, and moths might well hear them, however. Sounds this like, with frequencies beyond the range of human hearing, are examples of ultrasound.Infrasonics, vibrational or stress waves in elastic media, having a frequency below those of sound waves that can be detected by the human ear—i.e., below 20 hertz. The range of frequencies extends down to geologic vibrations that complete one cycle in 100 seconds or longer.
<h2>Answer:</h2>
<u>With radiocarbon dating scientists compare an object carbon 14 levels with </u><u>the fossil or rock for which the age measurement is required</u>
<h2>Explanation:</h2>
Radiocarbon, or carbon 14, is an isotope of the element carbon that is unstable and weakly radioactive. The carbon-14 method was developed by the American physicist Willard F. Libby about 1946. It can be used to determine the age of a rock or a fossil by comparing the specimen of the required or fossil and compared it with the carbon 14 sample. Carbon 14 decays at constant rate therefore an estimate of the date at which an organism died can be made by measuring the amount of its residual radiocarbon and comparing it with Carbon 14.
Answer:
6.060606...
Explanation:
To figure out velocity, you divide the distance by the time it takes to travel that same distance, then you add your direction to it. So the distance would be 1000m and the time would be 2 minutes and 45 seconds and if you convert the minutes into fractions you would get 165 seconds than you would divide 1000m by 165 seconds and you would get 6.060606... seconds as her average velocity