C . Record the time to complete a chemical reaction
Answer:
Explanation:
density of galaxies would be
times higher which is equal to 50.81.
It means in a cube that today contains one galaxy the size of the Milky Way, we would instead find 50.81 galaxies this size.
You can round this off to 52
Power=Energy
72,000/60 = 1200 watts
:)
The efficiency of the first Carnot engine is
n1 = 1 - Th/T
The efficiency of the second Carnot engine is
n2 = 1 - T/Tc
The total efficiency of the engines put in series is
n = 1 - Th/Tc
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For a cylinder that has both ends open resonant frequency is given by the following formula:

Where n is the resonance node, v is the speed of sound in air and L is the length of a cylinder.
The fundamental frequency is simply the lowest resonant frequency.
We find it by plugging in n=1:

To find what harmonic has to be excited so that it resonates at f>20Hz we simply plug in f=20 Hz and find our n:

We can see that any resonant frequency is simply a multiple of a base frequency.
Let us find which harmonic resonates with the frequency 20 Hz:

Since n has to be an integer, final answer would be 323.