Answer:
MATERIAL MEDIUM
Explanation:
Wave is a disturbance that travels through a medium and transfer energy from one point to another without causing any permanent displacement of the medium itself. The two forms of wave are the mechanical wave and the electromagnetic waves.
Mechanical wave is a wave with requires MATERIAL MEDIUM for its propagation. This means that before wave can be propagated at times, material medium is needed e.g a ripple tank. A ripple tank is a mechanical device that generates waves using an instrument called stroboscope attached to it. This kind of wave requires an external source before it can propagate compared to electromagnetic waves that does not require material medium for its propagation.
Answer:
yes 20 characters or more
Explanation:
To develop this problem it is necessary to apply the concepts related to Sound Intensity.
By definition the intensity is given by the equation

Where,
I = Intensity of Sound
= Intensity of Reference
At this case we have that 15 engines produces 15 times the reference intensity, that is

And the total mutual intensity is 100 dB, so we should




Therefore each one of these engines produce D. 88dB.
Answer:
(B) the sum total of all matter and energy
Explanation:
Universe comprises of all the matter and energy that exists in space. It contains billions of stars, planets and interstellar matter that is clouds of dust and gas. There is large amount of the empty space in between.
Universe contains stars as many as grains of sand on all beaches on the Earth. These stars are grouped into galaxies. Milky Way is one of the galaxies. Galaxies can be grouped into clusters and super-clusters.
Answer:
11.306 nm/s
or
113.06 atomic layers/sec
Explanation:
Hello!
First we need to know how much an inch equals in nanometers and a day in seconds:
Since <em>1inch = 2.54cm</em> and <em>1cm=10^7nm</em>
<em> </em>1 inch = 2.54 * 10^7 nm<em> </em>
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Also <em>1day = 24hours = 24*60minutes = 24*60*60seconds</em>
<em> </em>1 day = 86.4 * 10^3 s
Therefore the rate at which the hair grows in nanometers per seconds is:
1/26 in/day = (1/26) * (2.54*10^7)/(86.4*10^3) = 11.306 nm/s
Now, if 1 atomic layer = 0.1 nm this means that 1 nm = 10 atomic layers.
Therefore:
The rate in atomic layers is
11.306 nm/s = 11.306 (10 atomic layers)/s = 113.06 atomic layers/sec
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