Well there are areas of the seafloor that are spreading due to tectonic plates moving apart but there are also places where these plates meet and one slides under the other (subduction zones) as a result, the earth is not getting bigger since these two actions cancel each other out.<span>
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They require a medium to travel through
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Answer:50
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Explanation:
Let 
be the airspeed.
Let 
be the cross wind speed.
We know that,ground speed is the vector sum of airspeed and cross wind speed and airspeed is perpendicular to cross wind speed.
If 
and 
are two perpendicular vectors,the resultant vector has the magnitude 
Given,
So,the ground speed is 
ANSWER:
The study and analysis of light according to its component wavelengths is called spectroscopy.
EXPLANATION:
Spectroscopy is the branch of science that is concerned with the investigation and measurement of spectrum produced when matter interacts with or emits electromagnetic radiation.It helps us to identify atoms and molecules in the object.Spectroscopy is used to find out Dopplers effect (the red shift and blue shift),which tells how fast the object is comming towards earth or moving away from the earth.
