Answers:
40 mp/h; Vector
Reason:
120/3 is 40 miles per hour.
Velocity is a vector measurement.
^.^
- Amanda
Answer:
I think it's the most important part in this
Answer:
The observed wavelength on Earth from that hydrogen atom is
.
Explanation:
Given that,
The actual wavelength of the hydrogen atom, 
A hydrogen atom in a galaxy moving with a speed of, 
We need to find the observed wavelength on Earth from that hydrogen atom. The speed of galaxy is given by :

is the observed wavelength

So, the observed wavelength on Earth from that hydrogen atom is
. Hence, this is the required solution.