The moon's orbital and rotational periods are identical or the same, I<span>ts rate of spin is done in unison with its rate of revolution (the time that is needed to complete one orbit). Thus, the moon rotates exactly once every time it circles the Earth.</span>
Answer:
B) The cosmic background radiation is expected to contain spectral lines of hydrogen and helium, and it does.
Explanation:
Because Na⁺ ion lacks an electron and O²⁻ has two extra electrons extra, to balance the charge, we need 2 Na⁺ ions.
All ions, atoms and molecules want to get to the minimum energy state, and that state is when the ion, atom, or molecule is neutral, that's why all of them want to balance their charges.
Answer:
c. 2 m/s
Explanation:
The relationship between speed, frequency and wavelength of a wave is given by:

where
v is the speed of the wave
f is its frequency
is the wavelength
For the transverse wave in this problem, we have:
is the frequency
is the wavelength
Substituting these numbers into the equation, we find the speed of the wave:

The correct answer is 1.4285714.
In physics, velocity is characterised as a vector measurement of the motion's direction and speed. To be more precise, the rate of change in an object's position relative to a frame of reference and time is another way to describe velocity. The definition of velocity simply states the rate of motion of an object in a specific direction. It determines how quickly or slowly something is going.
Velocity = distance/ time
Thus time = distance/velocity
Here velocity = 350m/s
diatnce = 500 m
time = 500/350
time = 1.42857142857
t= 200m /350m/s = 1.4285714
To learn more about velocity refer the link:
brainly.com/question/18084516
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